Are the front pipes on the 4 and 5 inch kits the same because they are both 4 inches I figured they were the same because i am selling my 5 inch and getting cool dual and thought i could just use the front pipe off of my 5 inch kit but what part do i need to sell my 5 inch as a cat back? Looks like im kinda diggin a whole but im wondering if there is a simple answer besides selling my kit complete and having to order a new front pipe

What do you want for your 5" system???

If it is a 2006 or later then the front pipe part numbers are different. If it is a 2001-2005 then the four and the five inch utilize the same four bolt flange.

i just used my five inch down pipe with my four inch kit and it worked fine i just needed to make a coupler which i luckily had