Who is useing Header extensions?

In lieu of a dyno, desktop programs, or other tools that one would have to fork out cash to then take the time to test etc I’d think defaulting to the Direct Connection/Mopar Performance recommendations of extension length would be a good ballpark start....and maybe all that is needed for most. Stick 12”s on and roll, or split hairs and go mad......oops to late!!!.:eek:.:realcrazy: