I joined this forum in order to attempt to obtain information on upgrading the horsepower, appearance, and performance of my 2002 GMC envoy. It is a reincartion of my previous, which went to he'll and back, enabling my survival of a head on collision with a 2011 freightliner... I want to really deck this one out since it is extremely sentimental due to the circumstances it pulled me through. O am having trouble finding parts to increase horsepower on the 4200 and when I inquired about a custom 5.3 motor swap including new trans and nearing 475 HP, was told it would be approx $10500!! Any help would be greatly appreciated