Just wondering what size the cat inlet size is, or k16 turbo outlet diameter, so I can find a high flow cat to match up with it. Will the stock exhaust tips fit over a 2.5" pipe? Thanks for any info.

It does not matter. you take what ever cat physically fits then you would cut the inlet off fit a transition fitting say 5x4ish to fit it to the turbo and run what ever the outlet is. You really do not want to neck down out of a turbo in to a cat. the cat is a restriction in itself that's why the cat body is double if not more then the pipe that feeds it. Why not just lose the cats?

I have got to be able to pass emissions. I know I do not want to neck down. That's why I'm asking what the turbo outlet size is, so I don't buy a cat that does.

You might consider picking up a used catless system or cat bypass pipes and saving the one you have come emissions time.

I don't want a catless exhaust. Man, I hope I don't have to remove this exhaust just to measure it. I was hoping someone would know.

your going about this all wrong.... there a O ring... then what about the flange.. where are you going to get it... we use 3" OD cats and make it work with our flanges.. like this... simple...
I dont think the stock tip will fit over the 2.5" its 2 and 3/8ths...

heres one without thew cat.. 3" pipe... but the flange in the other side is not 3".... the ID is 3.25".\

Thanks for the info! I have a friend that has a laser cutter and it's computer guided. I'm not sure how he exactly does it, but he can fab just about anything and does great work. I just need to order some parts and didn't want to remove my exhaust to measure the turbo outlet diameter. He is very slow about getting things done, so I just wanted to get the ball rolling. Thanks for your info. I really appreciate it.

Cool! I can just use the factory flange like this guy and I can get those exact same cats too. He was able to fit the tips over the 2.5" exhaust tip as well!!! Too easy!

https://www.6speedonline.com/forums/...urne-fl-2.html