The TT one definitely won't, it has different flanges to the LCR. I cannot confirm about the S3 though.
The LCR has 2-bolt flanges apart from the DP to Turbo flange which is 3-bolt. The TT has 3-bolt flanges all the way through.
My downpipe-cat flanges are 3-bolt? only the cat-cat back flange that is 2 bolt?
Sorry, I mean in terms of upgraded DP such as Blueflame 3" , it goes from 3-bolt at Turbo, to 2-bolt at Cat/Decat, to 2-bolt at Cat-Back. The OEM one has 3-bolt flanges up until the start of the Cat-Back part.
The only problem I can see with using a TT DP & Cat/Decat is that you'd need to weld a new flange onto the end to match the LCR Cat-Back.
Ah no worries Jay; I wouldn't know as I still have standard crap DP!!
All will become clear when you upgrade, I hadn't a clue either until 3wks back.
I see you're going to AMD tomorrow so you're more than welcome to see what an upgraded DO sounds like on an OEM system