I was curious why my A4 has a fuel shut off at 130mph? I know in the manual it says "the tires are not rated for speeds in excess of 130" but what if I put z rated tires on? Is there an over ride or chip of some kind? I'm guessing the rest of the Audi line is the same. Accept for maybe the new TT. By the way, what does TT actually stand for? Josh Wheeler