I thought about doing the same thing and selling my stock exhaust. My area has seen little luck getting rid of the stock exhaust as there do not seem to be trucks other than the HEMI running around. I called Magnaflow and asked them to make me a kit with the 14" Magnaflow instead of the quite 22" and they said no! lol
I tried, since they won't produce a kit with anything other than the 22" muffler I'm getting the Mufflex 14" kit and tack welding the clamps in for support. The 22" muffler looks like a log under the truck IMO. My buddy has it and he's thinking of now buying a 14" muffler and welding it into his Magnaflow catback kit.....wasted money.