Did they weld the cat into the dump pipe, or added an extra one downstream into the system? or are you saying they replaced the stock cat with a high flow 100 cell unit?
Just trying to make some plans, and get what i need to do a similar mod. I'm undecided whether to put a cat into the dump pipe, or add a 2nd high flow 100 cell cat into the system down stream (re: after the stock cat somewhere in the cat back exhaust).
The US guys run catless, but I have seen a guy on this forum who welded a spun 100 cell cat into the dump pipe, and is still running the stock cat in the system.
I dont know how restrictive the stock cat is on the 6.