My dad used to have a 1990 mustang, with a CAT... we took it off and it gave us a lot more power, but we had to come up with some mods because we lost quite a bit of back pressure... but that way easy.

anyway, my point being... can you un-install the cats on an '05... just have a straight-thru exhaust?

I know that if you went in for servicing, they won't do anything because the CATs aren't installed.

Does anyone know if this can be done, without ruining the warranty.

 

I wouldn't recommend it..

You can **** your warranty right out the window...

You could however replace your cats with 2 High Flow Cats (leave the O2 sensors in of course) and replace the H-Pipe with an X-Pipe crossover, install some short or long tube headers... Then either run no mufflers (straight pipes back) or use a dummy muffler... (sounds the best this way). Max Horsepower and probably the best exhaust flow... IMO

 

I have been told that is up to the dealership I dont have cats on mine and they still work on mine when I have brought it in for service. You might what to ask first though. Hypothetically of course.

 

you can always punch out the cats. i did it on my 00 cougar v6 for 12hp! just pulled em off and rammed em out with a crow bar and cleaned it all up with a dremmel.

 

does the x-pipe kit let give you the replacment for the muff? =-) I want a good setup for the exhaust but dont want to pay 400-500 for mufflers if its not going to do sheet for me but make noise