Darn. Okay.nah it won't......too damn long, lol [hihi] go for the 3" anyway, isn't stock like 2.5" or something already?
and I'm guessing either a friend has one, or someone is selling one real cheap or something like that? 
Sure, the main difference in exhaust after the header is the location of the cat. You could just shorten it and re-weld the flange back on. Stock is actually slightly bigger (like .1in) than most aftermarkets, the restriction is in the resonators and mufflers. Feasibly you could cut out the factory units and replace with Magnaflow or Borla or whichever. Not sure if it would be cheaper though.Couldn't you shorten it and re-weld to fit?