I am thinking of getting an aftermarket exhaust system put on my truck, I have a 2004 f250 6.0 4door. I'm wanting a 4" without the cats, any suggestions?

 

You can post up a price request for the vendors and see what they can do.

 

I don't think it made a whole lot of difference on my truck.

 

If you're going straight pipe, then I see no reason to go with an aftermarket brand unless you want it for the stickers. I got mine from a local exhaust shop bent, hangers welded on and mounted for $100. 4" downpipe with a 2 bolt flange, then the main pipe. You may or may not notice any performance gains but it will definitely be music to your ears.