How big, on the turbo side of the catalytic converter, is the opening on the flange?

I'm sizzling up a 3" exhaust system while I'm replacing my clutch/flywheel. Alreadyordered upis a 3" In/Out 24" body Magnaflow to put midship where the factory mid muffler was, a 'Y' to run dual tips in the rear,and2 purdy Magnaflow tips to look good out back.I need to trash the cat of course. Everyone on this board knows how much power the diameter of that guy is causing us to lose. What I worry about is the factory flange on the turbo side of the catalytic converter having an undersized opening, as I will need to reuse that flange for my new system.
Is it 3", as I've heard the outlet of the stock turbo is close to, or is it smaller as the inside of the cat is? Or is there a place online that sells the flange alone that anyone has come across?
I would prefer to not destroy my hole saws trying to get through that chunk of steel, and I know the exhaust shops charge mucho dinero for a custom flange.

 

One of these guysfrom ATP sounds like the right flange:
http://www.atpturbo.com/Merchant2/me..._Code=ATP-FLS3
http://www.atpturbo.com/Merchant2/me..._Code=ATP-FLS3
The first one's 3 bolt and the second one's 4 bolt. I'm not real sure which we are. It's only 24 bucks, but if the the stock flange will work, I'll be happy to save the dollars, as the muffler, tip, y combo was about to $200 after my employee discount. And I've got the cost of the clutch set-up and it's timing belt time. Ouch.

 

Bump. People that have installed a test pipe or a hfc, do any of you remember-ish?

 

Call Brent Labree. That dude knows everything. 800-947-0199 orhttp://www.labreemotorsports.com/index.html