problem is you have 2 differant grips- and a viper is a touchy kind of car on handleing, you need the same type grip front and rear on a viper or any performance car for that matter
my car had PS2 in front and PZero's in the back when i bought it, never had trouble but since the rears are needing replacement, I am changing all 4 in spring
"Famous Last Words".............. be careful Spike. The problem happens when / if you have to 'go evasive' to avoid an emergent situation.
100% accurate prediction: When you DO finally swap to 4 GREAT matching tires like PS-2 or Cups or Gen-5 Pirellis, you will be amazed that what you thought was 'no problem' is now 90% better. Buy a TOP-NOTCH set, dont save $400 on contact patches.
like I said, I am not waiting for a problem to occur, I am fixing it with 4 new tires in spring (car is already stored for winter) and I bet it will feel a lot better indeed