VANOS began to rattle and had it replaced - $250.
Entire suspension was getting tired and replaced (front struts and rear shocks) - $500.
Window tint peeling - $300.
Blower motor - $200.
A/C compressor - $250.
Front lower control arms and bushings (including ball joints) - $350.
Stabilizer bars - $150.
Spark plugs - $70.
Fuel filter - $80.
Door locks are sticking - haven't repaired.
Glove compartment warping - haven't repaired.
Premature seat wear - haven't reupholstered.
Easy to say that this has been my favorite car I've ever owned. I've owned over 15 BMW's; many being e46's and M's, and this model seems to be better constructed and much smoother to drive.
The gears are very easy and seem less to shift through, but are easily maneuverable when a quick downshift is needed - NOT the case with any manual e46 I've driven. Sloppy gears - not as fun and "tight" to drive.
The interior is not holding up as I had expected, but there are no rattles that drive me crazy (again, unlike any e46 I've owned).
My M5 was an absolute NIGHTMARE - long story short, it needed a new engine after 3000 miles of gentle ownership. I re-entered the safer world of the non-M 3-Series. Came across a good deal from the original owner. Too bad I purchased around the time it started needing the 150k mile maintenance, but every penny has been worth it. I'm 17, and the seats feel very sporty for me, but at the same time they are extremely comfortable. With the new suspension, the car rides and drives much better (with the help of new front end components as well).
These cars are much much better than any e46 I've ever owned and driven, which is safe to say that e36's are better than e46 IMO. Yes, I know what I'm talking about, I've owned MANY of them, so I can commit to that comment. Take it from somebody that has weeded out the best choice of 3-series, e36 is the best by far. Yes, the e46 may look a little more modern and sleeker (that why I was continually purchasing them), but when it comes to the basics and construction, the e36 feels like it's built better and a lot more fun to drive. I cannot speak on behalf of the 318i, but the 325i is one hell of a car.
If you can afford approximately $300 a month on repairs and maintenance, you cannot go wrong.
I have averaged about 26 MPG city/highway. I don't have a heavy foot.
If you are wanting a 3-series, then I would strongly recommend the e36 as more of a drivers car. Handling is uncompromising. The e46 is more of a cruiser.