I have a 6 with the GT takeoff exhaust and it does the same thing the first several seconds after I turn it on, but only if I gun it. I either warm it up a few seconds or don't accelerate hard for the first minute of driving. I don't even notice it anymore.

 

Thanks for all the replies guys! Yeah, its VERY hard not to put my foot down on that pedal but I'm trying to resist. I will post pics soon!

 

Mine is horrible about popping loud(almost like a backfire) when it is cold. Once the pipes all warm up, it's good to go

 

Completely normal.