I have jsut fitted a eibach prokit on my E46, reason being on the highway alot, i have experience floatiness, i mean its not too bad and its comfortable that the suspension setup is that way. But when i was on eibach, the ride became imbalance, low ride comes with stiffiness over minimal bumps even i am on 16" rubbers 205/55/16, on highway it is not that fantastic at all, yes it did reduce the floatiness but other than that every bumps comes with a shock and absorbers is seem to be knocking hard on mounting.
So thus i asked around bimmers lovers or the mech at Performance werks, he told me no need to go top range, just try the ARB from UR F27mm or 330i F24mm and see the difference, with stock absorber and coils. I might go that way.
Any suggestion from all SIFUs out there about suspension setup, your idea will be much appreciated