does mopar cat back exhaust fit 3"down pipe?
or doi have to get 3"cat back?

 

absoloutly, it does and it will sound really loud sometimes annoying loud when u run it without a cat, thats the setup that i have on my car right know.
one extra part (o2 simulator) u need to buy to takecare of the engine light its not expensive.

 

it fits with an adapter piece. the mopar/borla exhaust is 2.5", so you need to taper the 3" down.

and as i stated before, you don't need an o2 simulator. if you want to run without a cat stage 1 will allow you to do that. if you are keeping in the cat then there's no need for either. don't waste your money on a simulator when stage 1 has so many more benefits that go along with it. actually any of the stage upgrades will work, but stage 1 is the most common.

 

whoa seems like psi said the same thing about 20 times already...lol thats funny, sorry tho psi...[sm=lol.gif]

 

Yep, and that's what I plan to be running in the near future. Maxxfab has an entire exhaust kit that way or you can just get the pieces seperately.

 

Isnt that like wayyy loud for a daily driver?

 

Too loud, is there a such thing? Not really, the turbo and the catalytic converter will keep it from getting to out of hand. Now if you were to get it with the test pipe that eliminates the cat, then it would be a bit much for a daily driver, especially if it's with a full 3" exhaust.