Ken:

I have installed the Indigo PCV Kit on my A4, it took about an hour or so however, I did it without having to remove any of the exhaust system. By the way the kit works great!

I am assuming you don't have access to the front of the engine. If that's the case, removing the exhaust "donut" (pipe threaded flange) can be a bit of a challenge. I would pre-soak the flange's nuts for a couple of days with best penetrating oil I could find.

I just replaced my whole exhaust riser assembly. I had a local welder manufacturer it from 308 stainless steel and I also purchased a new exhaust flange from MoyerMarine.com

Good Luck!
Steve