I have a 66mm exhaust side on my turbo.Yes , like stock .
ATR is out of business years ago , but many of the vendors on here could help you with your decision on what DP would best mate up with your exhaust system .
Everybody was new to this at one time , so keep asking questions and reading posts . Sam
Will it clear?
I test fit in my stock elbow for the downpipe it covered up the whole a bit .
I could always modify the rest of the exhaust some if needed.
I am more worried about it clearing the exhaust side of the turbo and the Westgate Hole lining up