Have you tried press bent 2 inch , the bends effectively reduce flow to 1/4 inch smaller. So 1.75 inch

Maybe a tapered exhaust with larger diameter up front tapering down at the end. Do start 2 1/4 then 2 inch from rear,muffler back.

Theory I read on this says as the gasses cool it keeps the gas velocity up. Some of the wrx guys do this 3 inch down to 2.5 from diff back. Slight drop in outright power but better for noise and response