I am by no means an expert so take this advice only at your own risk – some of this information may even be wrong. I’m just someone who bought an e30 without really knowing what I was doing and learned from the experience. The saying “buyer beware” is never more true than when shopping for a car. There are a couple of good guides already written that cover most of the mechanical stuff, so I’ll try to give you some tips that are not already covered elsewehere.

The best guide is this thread: http://forums.bimmerforums.com/forum/showthread.php?t=826530

Years & Models

1989 or later 325i or better yet 325is. These are the most modern e30s and offer the greatest opportunity for modification. Since parts from late model e30s and m3s can be installed on early model cars you should always check the VIN to find out the production information of any specific car. Read the Wikipedia entry for more information on how the e30 has changed over the course of it’s production.

• Early Model e30s (1982-1985): Most recognizable by metal front and rear bumpers.
• Late Model e30s (1986-1992): Bumpers have been updated to plastic and fog lights and air dam are integrated into the front valance. The engines are typically higher HP and the interior is slightly refined over early models.
• e30 M3: Distinctinve side skirts, fenders and rear spoiler are easy to spot. Of course, the real difference between an e30 M3 and any other stock e30 is mechanical: the M3 has suspension and motor ugprades throughout.

Mileage

Sub 200,000 miles is desirable, after that it doesn’t matter the m20 engine can go 400,000+ as long as maintenance is followed. Mileage isn’t really a factor in reliability or value unless it’s less than 100,000 or more than 300,000. Maintenance is more important than mileage.

Where To Find e30s

Try to find a car from an enthusiast: Check r3vlimited and bimmerforums.You may pay more but will get a well cared for car for less than the previous owner put into it. These guys often put $15K into a car and sell it for $8K. If you buy fom Craigslist try to find a one owner car. They are usually better cared for.

Title & Smog

Do not buy a car with a salvage title. Not worth the hassle and they are hard to resell.

Do not buy a car that hasn’t passed smog. You can spend a lot trying to get it smogged and it is illegal to sell a car without a smog certificate in California. Also, without a cat and OEM air box the car will not pass smog. Many performance mods will cause a car to fail smog automatically (visual inspection).

PPI

Arrange for a pre purchase inspection at a shop of YOUR choice. As I learned the hard way there is too much at stake and you can’t trust the seller to take the car to an unbiased shop. You’ll have to pay for the PPI, shouldn’t cost more than $130 but can save you much more if the car needs $3k work just to be roadworthy

Taking It Home

Plan to have the car towed home or to a shop for a once-over or for critical repairs after you buy it, unless you bought the car nearby. You don’t want to have the timing belt break and ruin the engine, or some other catastrophe.

Prices (by Category)

• Neglected worth $1000 or less

  My car started out in this range, but I didn’t realize it and paid too much. Cars in this category have not had basic maintenance, wear and tear parts haven’t been replaced (bushings, suspension, radiator, belts, water pump). Some have only cosmetic work put into them and can be hard to identify as truly neglected because they may have after market rims, cone air filters, HID headlights or other superficial enhancements. Cosmetic things are cheap, easy and fun so don’t pay for someone else’s decorations. Beware of body kits. They can be poorly installed or be falling off and the community tends to frown on them. If you buy a neglected car have it towed to your garage, do not plan to drive it home.

• OEM worth $1600-$3000 (maybe as high as $4500 depending on market)

  I refer to an OEM car as one that doesn’t have any (or many) aftermarket parts and is generally an e30 the way BMW built it. A car in this range should have had all the basic maintenance performed recently. Probably has stock rims (basketweaves or bottlecaps), there may be some interior wear and tear (see interior below) but generally the car should be mechanically sound and in good condition. Car should have an un-cracked dash, new timing belt, new water pump, maybe a new radiator, recent oil change, low mileage brakes and tires to fetch the upper end of this scale. Bilstein shocks and Eibach springs are a plus but remember suspension goes bad eventually and the owner would have to replace those just to keep the car drivable. Bilstein shocks are not an upgrade for e30s (so I’ve been told): that combo just reproduces the feel of OEM shocks. Engine may be a little dirty. The only people who clean engines are OCD or do their own repairs and this car was probably serviced at an indy shop or BMW dealership. Expect torn seats, some missing trim pieces, paint scratches or dents. Also plan on $1K or $2K repairs. Less if DIY.

  Note: Beware of neglected cars sneaking into this category because the market for e30s is lucrative. Beware of people who have neglected cars with a few cosmetic upgrades trying to sneak into the OEM or Modified / Clean price range.

• Modified / Clean worth $4500-$8000

  Keep in mind that a good condition daily driver e36 is about $4500 – an e30 fetching the same price needs to compare to that newer e36 to qualify. Cars in this range are either “clean” (very well preserved OEM cars, over and above what you would see in the OEM category) or “modified”. A modified car can have many cosmetic blemishes but have so many upgrades that the price is justified. Modifications are hard to value but they can include (in order of how common they are): air intake / air meter (afm, maf) upgrades for increased HP, ECU (computer) chip upgrades for HP, suspension (GC or other coil overs), LSD upgrade (watch it, this sometimes does nothing to improve the car’s acceleration unless other mods are done. BMW usually gets the LSD right when they make the car), engine swap (usually swapped cars start at  $7.5K though may not add much HP), fuel injector upgrades, stroke mods, bore mods. Some people with clean cars want the high end of this price range but that’s a losing proposition for you, the buyer. Save your money and find the same car with mods that justify the price. An engine swap offers the greatest HP value of any mod, benefits of other mods are debatable and complicate getting your car smogged.

• M3 Territory worth $10K+

  Anyone asking more than $10K is in M3 territory. I’m not sure how to price M3s but I’ve seen them for sale for as little as $10K (but in need of work, usually body work). The only non-M3 cars that should be in this category are modified AND clean cars. They should have swapped engines, pristine interiors, suspension upgrades, aftermarket rims and tires and excellent paint jobs. All the wear and tear parts should have been replaced recently. Engine and entire car interior and exterior should be clean and generally blemish free.

Mechanical

• Get To Know e30s

  This is probably the VERY best tip I can offer: If you’re not familiar with e30s except as a passenger you should go to the Pick N Pull or other auto dismantlers and get to know the cars as intimately as possible – pretend these are cars for sale and evaluate the worthiness of them. How is the engine, suspension, radiator, interior, etc.? Look for things that are missing, broken or in poor condition: lots of e30s for sale are missing bits but you won’t know that if you’ve never seen an e30 with that part before. Wear gloves, touch things – hell, take things apart, the Pick n Pull doesn’t care (and see mechanical below)! For extra credit read the first 2-3 chapters of the e30 Bentley Service Manual (you can find it as a PDF if you are diligent).

• Recent Work

  Owner should produce receipts for recent repairs. Timing belt and water pump need to be changed every 60K miles. If the owner hasn’t done at least this then walk away (or offer very, very low): the car is neglected.

• Easy Fixes

  Beware of issues dismissed as being “easy fixes”. Some people bring these up as a smokescreen for more serious problems. “Runs great, all it needs it a water pump. Easy fix.” Ask yourself, if it was so easy then wouldn’t the previous owner have fixed it? What else didn’t he fix that’s going to cost you?

• Odometer, Instrument Cluster:

  Can be fixed if it’s not working but is not worth the hassle of unknown / incorrect mileage. I would avoid. When you start the car do ALL the indicators light up? People sometimes disconnect lights so they don’t have to look at them, or to pass smog / mechanical inspeciton and therefore problems go unchecked. Cluster lights are easy to replace but can hide other problems if left burned out or removed.

• Engine Off

  How clean is the engine? A clean engine usually but not always indicates good maintenance. Are any hoses cracked or leaking? Those will need to be replaced, plan $12-$24 for each hose, $100 more if you’re hiring a shop. With the car off, but warmed up, check the dipstick. Is oil level low? Leaks, poor maintenance. Is it milky or creamy? Coolant leak, show stopper. Check the coolant reservoir. Any oil in it? Head gasket leak, another show stopper. Look under the car with the engine off. Any leaks, oil droplets forming? Oil accumulation? Are the rubber axle boots torn or cracked? Use a flashlight here. Axles are $100 each used but installation can be trouble. Rebuilding them is cheap but labor intensive and messy. Visually inspecting the spark plugs will tell you so much about an engine but the seller may not allow you to do that (or may have replaced them just before putting the car up for sale) so get a PPI and make sure that’s part of the inspection. Expect that anything leaking would need to be replaced. Check the rear differential, steering rack, front oil cooler, front radiator, oil pan. Bank on average of $250 per part (used price, double for new) plus the same in labor.

• Starting The Car

  Car should idle around 750 RPM, though 900 RPM is acceptable. Lower idling indicates air or vacuum leaks but may not manifest itself unless the engine is dead cold. May be cheap, may be expensive / elusive to fix.

• Driving The Car

  Well covered in other resources.

Exterior

• Rust

  No California car should have rust. If it does then don’t buy it. Rust is well covered in the link at the top of this guide.

• Color

  Avoid custom paint jobs, unusual colours (like green or blue) — unless the car is absolutely immaculate and requires no body work whatsoever. Replacement body parts will require painting and if it was a custom job the car may have overspray or fitment issues from poor re-assembly. If you have an apline white e30 and need a new fender you can go to the junkers and get one for $100, but if it’s alpine green you will have a very hard time finding a donor car that color. Only go for an usual color if it’s a BMW original paint job and immaculate. Or you absolutely love it. The community tends to frown on non-BMW colors. People notice but maybe you don’t care. My car is not a BMW color but it gets loads of compliments so there is always an exception. However, my car’s custom paint has been a load of trouble for the exact reasons I mention above.

• Body

  Scratches and chips can be touched up but expect anything else to cost $1500 minimum to fix, unless you can replace the part entirely (see previous note about colours.) Almost all exterior trim can be found cheap. Brand new kidneys are $40, light grills are $130 new / euro style or $15 from the Pick n Pull. Door bumper rails are more rare / expensive unless you get them from the Pick n Pull (but it may take a while to collect a complete set of the same quality).

• Lights

  Make sure all the lights work, if any lights have been “smoked” consider that they may be illegal in your area and need to be replaced. Or the quality of the painting might simply suck. Tail lights run $50-200 for a pair depending on quality, cracks. See next section on “interior” for the reason why I think lights are important.

Interior

Note: If you don’t care about the car’s interior then you can ignore this section. However, the interior says a lot about how a car was cared for: If the owner didn’t bother to replace a $2 light bulb they probably didn’t do any of the major repairs either.