Hello I just purchased a 02 73 with 100k on it. I have searched and tried to find the benefits of the 4” vs the stock exhaust with a muffler. I know I don’t want straight pipes and all I can found is comparing the 4” to stock with straight pipes. What are the benefits of a 4” turbo back with muffler vs the stock with muffler? I have already put on an intake and an exhaust is the only other thing I wanna do to it. Its gonna be used for truck things and towing my 8k lb camper. No programmer or anything else. Is it worth getting a 4”? If so which one would you suggest? Thx everyone!

I installed a Walker RV muffler model# 21470 in current truck. It was $50 a few years ago at Summit Racing but I just checked and it’s $60 now. It is a straight thru muffler with 3-1/2 inlet and outlet. It is the same diameter as your stock exhaust and can be installed in place of the stock muffler with little modifications from a muffler shop.

I went with a 4” MBRP turbo back system with a muffler for my other truck and I can say that the Walker RV muffler is noticeably quieter with basically the same performance and EGT drop as the MBRP.

If the the truck is staying stock or anywhere close, the stock exhaust size is sufficient. The down pipe will be the smallest section at 3” but the turbine outlet on your turbo is also 3” so it’s not a lot restriction if any.

Hope this helps.

Good luck!

I went with Diamond Eye 4" turbo back. I saw significant improvement over my stock exhaust BUT I had a plugged cat. I paid $250 shipped, IMO it was worth it in my case! However, I can't compare it to a stock exhaust that was functioning properly.

The biggest advantage to installing a 4” that I have found is that you can remove the downpipe if needed.