Im looking into putting a ss exhaust on my truck. Im want to do a 4 inch system. im wondering what i will gain or lose from going from stock to 4 inch from the turbo back? any thoughts or suggestions appreciated.
also where can onw buy a 4inch stainless dp?

 

If you buy a complete system, it should come with the down pipe.

 

You will pick up some HP ( about 20 to 30 ) the exhaust temp will drop about 100 to 200 degrees and it will sound much better. Going with SS is up to you but there is no gain over a coated system but it looks better.
Look around for the best price they are all over the place, and free shipping.