I own a 1997 BMW 318iS, it's almost identical to an M3 other than the engine which is the reliable M44 4 cyl. A solid car that is nimble and gets 38mpg highway, 24mpg in town, an average of about 30-32mpg. The S version has a lower M3 like sport suspension, wider stance, and mine was ordered with M3 rims which perfectly suit the car without being gawdy. Regular maintenance will give you a reliable smooth ride. Torquey engine redlines quickly with moderate gas but shifter seems longwinded compared to a 1980's Manual. Nice interior, mine has heated seats that warm up quickly in two modes. Multiple cabin vents. May be small for a larger person. I'm 6' tall and fit nicely. Very fun to drive.
Heated seats, sports suspension, smooth shifts, torquey engine and drivetrain. Zippy car in town or on the highway. Smooth rider for a smaller car. Easy to work on. Maintenance is vital for reliable fun ownership. Don't wait for it to break on a BMW, and have it done right if you don't know how. :)
Small trunk even the rearend seems big for the rest of the car.