It’s been a long day. I think I’m completely exhausted. Ha! Wait, not funny? All the voices in my head laughed. I was originally going to go 3” since the turbo exhaust flange is 3” but I read an article that convinced me 3.5” was the way to go.
https://www.motortrend.com/how-to/mo...ust-test-tech/
You can read it or take the short version…on a Supra running 19psi of boost they baseline at 527hp. Then they swap the whole 3” exhaust for 3.5” all the way back and it makes 610hp. I refuse to go to all this trouble and expense and potentially give up 83hp because of exhaust pipe! Used a Vibrant resonator as a muffler and transitioned to oval pipe at the 90 so I could easily weld in an oval tip.