consensus at the time I got mine were that>
koni > bilstein. Might be apples to oranges but I had bilstein/dinan on my E36 M3 and they seemed to give a firmer/harsher ride than the present car (E46 M3) with koni/Eibach.http://forums1.roadfly.com/preferenc....php?img=23351
try m3 forum dot net - objective comparison
for suspensions. From what I read, if you want to spend money on coilovers, KW2 with progressive springs will give marginally better handling but better ride than stock. Cheapest is probably Konis. On whole - not just E46M3 or BMWs, Bilsteins seem to be harsher than Koni setups with same spring rate.