Friday night I installed a 5" Stainless exhaust with a 6" tip...to replace the 4" setup I had been running for the past few years.
4" is supposed to be good up to around 450-500 rwhp, which I exceeded quite a while back.
I feel like I gained 20-30 rwhp with this exhaust...truck pulls harder at the top end of each gear better than before.
I really need to re-dyno it and see how close I am getting to the 600 rwhp mark