I've got 255/40 on the rear and 235/45 on the front with JIC coilovers... These coilovers are sssoooooo stiff!!!!! Lets just say they are the equivalent of an iron bar in place of the coilovers... When i jack up the car, the coilovers only push out less than 1cm... So i find the ride very harsh, but awesome round corners, feels like its on rails!!! And around the track is awesome as well...
As for diff bounce, i got a 2 way nismo LSD, and i don't notice any sorta bouncing, just wheel spin...