I have a 2004. 5 "610". 3500/dually
I recently had the huge muffler removed by my muffler shop, and had them weld in a new 4" piece. Only $36! Sounds great, actually quieter at 60-65mph than before and my mile per gallon is up by 1 1/2 mpg. The wife has been so sweet to get me the AFE stage 2...