Did a search and couldn't find anything so I figured I'd ask. What is the most people have gotten with nothing more than a tune? With all the ultra conservative factory tune and all the nannies placed by GM I can't image 305/323 being all that close to peak, given how limited they made for the glass transmission.
Sent from my ASUS_Z00TD using Tapatalk
Sent from my ASUS_Z00TD using Tapatalk