Originally Posted by phunk

ridiculous... different tires F/R do not make a car twitchy.

for a long time, i have had powerful cars with traction issues. i almost always have a completely different tire front and rear because i go through drive tires much faster and i always want to try something else to see if i can get it to hook up (straight line) better.

a few reasons his car feels twitchy to him after changing his rear tires:

1: new tires are slick, takes a day or two to get off that nasty coating
2: new tires are not worn in to your camber, so your riding on much less of the tire until it wears in which can take a week or so depending on your driving habits.
3: RE-11s track worse than stock, so hes feeling the rear end follow grooves in the road and hes not used to it yet. My RE-11s on my 370z instantly felt more "twitchy" when i put them on, its just tracking. Pretty typical of high performance tires, and definitely a noticeable different when coming from **** tires like our stock ones.

aside from that, there is NOTHING HAZARDOUS about running different front/rear tires, that is ridiculous to say. you can tune oversteer/understeer with tire make/model just as well as you can with tire sizing. the only thing that you may run into is a slight differences of how the different tires perform as they both heat up... but you will never notice that on the street, only someone on the track doing lap after lap is going to notice a variance like that.