anyone do highflows or Y pipe im interested in doing these but not sure what kind of gain ill get, and if the exhaust will get louder -
any answers?

 

coondog 05 has the larger y-pipe on his truck along with the headers. did not seem any louder than usual.as for the cats, most people just ram a piece of pipe through the cat, opening it up. and by doing this you still get to use the 02 bung. instead of purchasing a new cat and having it installed