coupedawg

I have an 07 C6 A6 with B&B headers,X-pipe with high flow cats & bullets.
If i tune my setup with a Diablosport predator,what tune will yield the best
performance,the "performance tune" or the " 91 octane header tune?

Thanks for any suggestions!

ProgGod

Both are going to give you a ****ty tune with mods. If you plan to upgrade your cars parts, pay for a custom tune. Otherwise you could damage your engine, or at very least won't see the hp gains you could have gained.