KL V6=win if you can work it out
Turbo=scary for a DD
Streetbike=useless in winter anyways, no fun at all until summer
Civic=tempting, but you can't get any nicer than the P5 you've got!
What I think=I'd like to see a KL swap (I'd also like to help with it!), or I think you should begin building a proper fun track car--by that I mean RWD