So here’s the deal. I currently have a 4” turbo back exhaust. The down pipe fits like S#!T. It beats against the spring shackle and the trans dipstick tube. It is driving me crazy. A friend of mine that works for Dynomax got me a stainless turbo back system but the down pipe is only 3.5” and it necks down to 3” at the “cat” flange. The other side of the flange is the omit pipe and it goes up to 4” and that’s how big it is the rest of the way back to the tail pipe and then it has a five inch tip. I am definitely going to fix it where it necks down to 3” but the question is how much am I going to lose going to a 3.5” downpipe from the 4”? Would it be worth getting a 4” downpipe from another vendor and if so, who makes one that fits half way decent? Or should I just through the 3.5” Dynomax downpipe on and go with it? Decisions decisions.