I've had the best ride setup in 2 previous BMWs (both e30s), one was a cabrio daily driver and the other a track car... the coilovers from Ground Control are matched spring rates that you decide (they can help you) and in my cabrio, i could have it lowered so far that a sideways can of soda couldn't fit under it, yet it drove so smooth, that when i drove over (the old time parts of town) brick (as in red bricks) roads, my cd-player wouldn't skip..in fact, it only skipped when i would get this car mildly airborn on some parts of the freeway i could manipulate (for fun)... the car(s) have never bottomed out and have always performed flawlessly. they do take a few months to settle down, but after my first install, I really like them.
on the cabrio, i ran 350/500 rates, and for the weight ratio, that was perfect. but call them and talk to them and afaik they all drive BMWs and know first hand how their stuff works and feels... I told them i wanted my first set for 'spirited street' driving and summertime auto-cross style, and also, a side note, i used Tokina illumina (i know, cheapo) shocks...but they all worked great.... I do recomend Koni's these days though... if you can afford them, they're the best.
so, without further a due
try
this link here to see what they have for the e46... i will be going this route in a few months if you want to wait for me to complete it before you buy it... if you're in the seattle area, you can drive it too... but it won't be till around June/ July this year
ps, they are also completely awesome when it comes to replacement parts too.. I lost my tool, and they shipped me a brand new one free of charge. also, the rings never got damaged on my track car even after constantly messing with them over and over... imo, for a few hundred bucks, ground control is the leader and also has a lifetime guarantee too.
also, I have the 2002 325ci with sport suspension as well, and if we calculate the price we can sell our sport springs for, it makes their kits very affordable.
hope this helps.