Everything you need to know about buying a used E46 3-Series — body codes, model years, option packages, recalls, and what actually matters. The advice you'd get over a beer.
The car you're looking for is body code "E46" — BMW's 3-Series. They began making these in 1999. Beginning in 2000, BMW started offering 3 years / 36,000 miles maintenance included with all cars. This includes oil changes, brakes, wipers, broken cupholders, everything. Purchase the extension if you get a low-miles car.
1999–2000: Either a 323 (165HP) or a 328 (~200HP). 2001 and up: Either a 325 (165HP) or a 330 (225HP). Drive them all and make the best choice for you. You know which one I'd go for. 330s run about half a second slower than my 540 in 0–60. Pretty quick.
PP — Premium Package: Electric gizmos. Power seats, sunroof, auto-dimming mirror, rain-sensing wipers. Leather in '02.
SP — Sport Package: Firmer suspension. Larger wheels (17" vs 16"). Titanium trim around the headlights. Round fogs vs non-Sport rectangles. This is the styling cue people talk about — you can tell right away what you're looking at by the headlights.
CWP — Cold Weather Package: Heated seats, headlight washers, fold-down rear seats with ski pass.
PDC: Park Distance Control. Beeps when you get close to objects. Steptronic: BMW's automatic that you can also shift without a clutch. NAV: Navigation — worth having.
There were a few thousand 3-Series (and 5-Series, X-Series, pretty much everything) produced from early to mid 2001 that were recalled due to a bad auxiliary fan switch that caused overheating. In extreme cases — about ten nationwide — this caused fire. Verify any candidate car has had this addressed.
Sedan vs Coupe: Two doors vs four — but also different headlights and body trim. Coupes have body-colored trim; sedans have black mouldings.
1999–2001: Essentially the same cars. 2002: Facelift — reworked front and rear lights. The 2002 coupes are the same as before. The 2002 sedans got the updated look.
Wheels: They vary by model and year. 323s have different sport wheels than 328s, as do 325s and 330s. Clear? I didn't think so.
Interior: Small nav screen pre-2000. Larger 16:9 ratio screen from 2001 up. The 330 has chrome rings around the gauges.
Warranty Extension: Available from the BMW dealer — extends the standard 2000+ included service to 4 years / 50,000 miles. Worth looking into at around $450.
CPO — Certified Pre-Owned: If purchased from a BMW dealer, they may have already applied this. All indications are that it costs the dealer $1,000–$1,250. They usually charge $1,500 or so. Any more and they're screwing you.
Steering retrofit: BMW offered a steering retrofit on 3-Series from 1999 on because owners complained it didn't feel as tight as pre-'99s. The 2002 cars have this fix. Inquire whether any candidate car has had the updates and recalls applied — ask to see the VIN maintenance history from a BMW dealer.