The problem here is that you don't really know what it is you're trying to accomplish. You simply have this vague notion of wanting something "better". A fresh stock suspension has more than enough performance to tackle the twisties (well, at least the ZSP or ZHP equipped cars)... and KW v-anything plus roll bars is still going to fall well short of a good track setup.
Let's try a different approach here. What is it about your current setup that you don't like and feel needs to be improved? What, if any, qualities of your suspension do you like and would prefer not to change?
Honestly I think the best advice anyone can give you right now is to sign up for some driving lessons (track events) and learn to exploit the capabilities your car has so that you can start to recognize what might need to be improved.
04 IR 330i ZHP | ESS TS2+ SC | MagnaFlow "headers" | KMS 3.64 LSD | AST 4100 550/650| APEX ARC-8 18x9 | H&R front sway bar | Vorshlag camber plates, RTAB limiters | TMS subframe & swaybar reinforcements | UUC SSK & DSSR | UUC TM & TME | BW motor mounts | Dinan strut & shock tower bars | vaio 4-bolt oil pump