shift kit is an easy, cheap mod right... well I read this off zzp's shift kit,
"Our transmission shift kit improves the shifting of any 4T65e. It works on the standard and HD versions of the transmission and can be installed in 2 hours. Shift kits can increase the chance of hard part failure but they do keep the clutches from slipping and burning. We do not recommend this kit for cars running 20" wheels."
ok well I have 20" rims so my question is, WHY NOT ?