I Have 3" pipe from my cat to muffler. Do i need to get a cat back system or can i just add a Flowmaster muffler and get the same result?

 

also should i get 3" in and 2.5" out
or 3" in and 3" out?

 

probably get real good results dumping the whole stock exaust and getting headers, after market cat, and a good cat back. Even though it has the 3" pipe form the factory, the stock exaust is still pretty restrictive. Adding an aftermarket cat back will give a little extra power but not as much as whats mentioned above.

 

If the pipe is stock it is not mandrel bent, which a mandrel bent one will benefit you. Like said, replacing the entire exhaust at once would be a great idea.

there are other mufflers besides Flowmaster you know

 

Like mentioned above, to get the best results get a cat back set up... but if you already have manderal bent pipes no need just replace the muffler. To tell if you have manderal bent pipes versus stock pipes is that when you look at the bend of the I-pipe that runs over your rear axle if the pipe has ridges going around the corner it its factory bent pipe, if its smooth its an aftermarket manderal bent which flows better. You can either get a flowmaster 80 series with single 3" in dual 2.5" out or if you dont car for the dual exhaust look you can get a 2 chamber 40 series with single 3" in 2.5 or 3" single out. Also Dynomax sells a nice cat back for the thirdgens. If you wanna spend an extra couple bucks, SLP makes a sweet stainless steel cat-back. As for headers hooker supercomp shorties or SLP stainless, agian SLP's are a little bit more expensive. Hookers are nice, i have a pair and ive been satisfied. Hope this helps...

 

Thanks for all the responces, looks like i have some decisions to make. I checked my pipes and they are stock so i will go with the 3" cat back followed by the cat and headers.

should I dump the A.I.R. or get headers with them?
what are the advantages and disadvantages?

 

If the state that you live in doesn't have any smog standards then i would say dump the A.I.R set up. and goes with some headers w/o A.I.R. but if your state does then go with smog legal headers. By removing the A.I.R. set up will free up some hp a little bit and if you remove the A.I.R. might as well ditch the cat for an off road straight pipe.