I have a stock 2004.5. I am looking to do some upgrades but not sure what all I will need. The first thing I will do is some gauges (FP,EGT, and boost). The progression of the other upgrades I am planning are intake (afe stage ii w/a proguard 7), 4 or 5" exhaust, and then an edge ez box. My question is for this set up do I need 4 or 5"exhaust, or more correctly which will help me out more with horsepower and mpg. I also don't want an exhaust that the resonance will hurt my ears. If there is a 5" exhaust that is not obnoxiously loud inside of the cab I would not mind having 5". Also is afe stage II with a proguard 7 the best way to go. I know quadzilla, bully dog, airraid, and others have relatively the same set up. The afe set up is around $455. Is there any other set up that is comparable that is not near as expensive? I know you get what you pay for, but sometimes you also get the name you pay for which is comparable to a less recognized name that you can pay less for. I would appreciate people to let me know their experiences and their opinions.

 

If yours is a 2004.5 you should have the 4" exhaust already. Just get a replacement muffler from Mark Craig at DPP. The AFE Stage II is the way to go if you like ALOT of turbo whistle. I had one and took it off, a little too loud for me. If you do an air intake system go ahead and pull the silencer ring out while you are in there.

 

I thought on the 2004.5's it was 4" to the CAT and 3 or 3.5 past that. The person that had the truck before me took the muffler off and left the CAT. I would not mind taking the CAT out and putting and aftermarket muffler if that is all that is needed. Not sure if it is ok to take the CAT off or not and not sure of the difference in perfomance of having a CAT versus not having a CAT.