You could just do propane injection on the tailpipe right next to a spark plug or something, it would totally bypass the midpipe alltogether.
Nitrous -> plug... NAWS!!! Just rice out your car and it'll shoot fire under normal revving. It worked for Brian and Dom.
You have two choices: 1.) Save your money and buy mods that will actually give you more hp. 2.) Have a stang that can shoot flames from its exhaust and get beat by a bone stock SRT4.
As long as the SRT4 starts out behind you, just spray flames over his hood and watch the front end melt, you win!
i saw a riding lawnmower shoot flames out its tailpipe today, the backfire sounded like a shotgun blast. scared the sht out of me