I myself told them to cut them off right before the 2ndary cats come on. Since I liked the mandrel bends after the DP.
The production piece will more likey be after the DP's with 2.5' inch piping all the way back like mine.
I believe he will be charging 1400-1500 installed. Thats for the polished stainless steel. Like I said before their stuff isnt cheap. But look at their work. Its quality stuff. Rather get a great job done the first time.
Previous - E90 335i, E82
Current - E89 / Range Rover sport Super charged.