What car?
899s benefit from sporting suspension upgrade, complete with anti roll bar.
If you have sporting stuff already, then a 35-40mm drop isn't to extreme. But it will be a lot firmer, but not crashy. Standard (sporting) shocks do still work and I haven't bottomed mine out yet.
I am in the process of fitting mine with poly bushes up front. Haven't had it on the road yet, but I have heard good things, so long as you go for red over yellow.
But as cento186 said, it is all compromise, handling over comfort, or comfort over handling.
If you only want a slight improvement, stick a new good quality set of shocks on and poly bush the front. You should still have change from a hundred quid and it will improve it no end.