Thanks Mike and Johan. I've checked under options and it does say diablo tune. I've always been a stickler for fuel and prefer Mobile 93 when I can get it. I used the same tuner in my 06 C6 and really noticed a difference but didnt notice in this car. It could be because the motor already puts out ...

I'm sorry for not originally posting correctly. I have a 07 Z06 (Brand New Stock) that I have recently programmed with my U7194 (which was recently programmed in my 06 C6). I have noticed absolutely no difference. As with my 06 C6 install, there was no options for 91, 93 or anything but the Diablo ...