Originally Posted by rushdude

About the diameter of the stinger, I am pretty sure that the legal limit for 1/10th gas is 5.0mm and the 1/10th open it is 5.2mm. Anything above that isnt legal. I have run a 7.0mm pipe, and in my opinion it isnt worth it. It turns the car into more of a straightline car. Here are the rules on stinger inner diameter, I just found my roar book.

.12 roar
.12 open 5.2mm
.15 roar/ifmar 5.2mm
.15 open 6.5mm
.21 open 8.0mm