Alstann

I disagree with people saying different compount front and rear affects the handling adversely. In terms of an unsetteled feeling at highway speeds, or with quick left/right manueuvers, it's most likely that the new tire that you purchase has a softer sidewall. All the 370z's, esp. Sport package equipped 370z's, came with sporty, stiff-sidewall tires. Switching to a tire with less agressive characteristics, such as a lower rated performance tire or an all-season tire will affect the stability of the car.

Anecdotally, I personally bought all-seasons for all 4 corners of my car (Bridgestone Potenza RE970AS), and within 30 minutes of driving city and highway, I realized that my car was so unstable compared to the stock RE050A. All I did was change the front tires to Potenza S-04 (extreme summer performance tire), and leave the rears as all seasons, and the car regained it's stability at high speeds and with abrupt maneuvers.

Trust me - it's all about the quaility of the tire, and the sidewall stiffness. Different tire compounds front and rear is not a bad thing. Of course, this only applies to the stability of the car.

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