dude stay away from flowmaster....borla is one of the best catbacks u can buy why switch out of that?....i have a flowmaster on my car right now and its coming off asap!

 

As has been mentioned, don't waste your money!!! Put it to use in some other way.

 

Im voting with everyone else. Flowmaster sounds great but loses hp. The reason they are saying you wont gain much if anything with 4" over 3" is because your 3" isnt going to be used to its full potential let alone 4" so your car isnt really going to notice the bigger exhaust piping.