10yrs ago I put a complete 2.5" system in my Challenger, 340, w/Dr Diff relocation kit, no issues.
Just swapped in a 5.7, bought the TTI shortie headers and head pipes, and it bolted up perfectly to the existing system.
TTI is 1 of the few vendors that you get your monies worth, quality product.

I will say, I didn't spend the $400 they wanted for tips, got some for 1/2 that.