I used Mobile Man Tig welding service with excellent results.
I cut, fit, mocked up the pipes how I wanted them placed. He tacked them while on the car. I removed them and he finished the welds and also added an O2 bung.
Full stainless system on my BDR.
Cost $150.
There's a pic on his website.
https://www.mobilemanfabrication.com/