I'll throw up my EXPERIENCE for you guys to bash around. I have a rebuilt 22re, comp cams 252s cam (low rpm range). My exhaust is 2 1/4 all the way back and exits like stock. I have a magnaflow (open style) muffler pn 11225 and a magnaflow cat. The truck does not accelerate much above 4000rpm. I noticed a big difference in responce by modding my AFM. It became much more responsive even at lower rpms. I would like a little more bottom end and if i did it again i would probably try 2" all the way.
I also think playing with ignition timing would make a difference. setting it by turning it till it pings and backing it off does not work well for me. I find i have more power if I retard it even more.
