Congrats on the new truck, those little jeeps are awesome. It should serve you well.
DP Mag did an article on them a while back, the cat-back from the 3.7L is a bolt on. With the exhaust, Edge, and a K&N filter it picked up 50HP and 35ish torque at the wheels.
Do you happen to know the weight difference between the 245 and 265 series tires? If there is a big enough difference, that could account for the loss.
Correct. Its for my 03'. I dont know about the other companies but ACDelcos is Part # ACF-TP3012, and as far as I know, they are interchangeable through all the years.