Would second gear be better at launch? Got a 2015 - 8 speed and there is a funny exhaust note after each shift, is that the retard you talk about? I'm dying to take to track but don't want to embarrass the car with me not knowing what to do.
The fart sound between shifts is called torque management (timing retard to lessen the blow between shifts) With it removed via tune on my 5-spd it'll pick up 3/10. Your 8spd is good for 516lb/ft - so I'd dump that (5-spd not even good for the 470lb ft of the 6.4L!)
