I love my GXP. I tested the GT and the GXP. There is a noticable difference in the two cars with respect to three driving characteristics. (1) accelleration is clearly superior (2) Braking is clearly superior (3) Handling and suspension are clearly superior. Yes, in my opinion the extra $$ for premium fuel is well worth it for the better driving experiance. Remember, the GXP beat the BMW at Nurburgering.