I believe this is the tt one, not sure if that ebay one is the same.
Audi B5 A4 Quattro 1.8T > Engine > Intake > Diverter Valve > ES#581 Diverter Valve, 225hp Audi TT Version - Priced Each - 06A145710N

not to hijack the thread but i am also considering getting a apr or giac stage 1 tune for my car. Is it likely to cause a boost/vacuum leak?

I know my stock k03 is in good condition, my car only has 130k miles currently.

I was planning on getting a boost gauge soon though to ensure it has the correct psi, what is the stock psi reading supposed to be?

 

Don't worry, you're not hijacking it.
It's not that it always causes A leak. Its that the higher loads on the hoses ends up causing a leak eventually.

And I had the same question as well about the stock PSI

 

Hey guys, so I ended up making my own boost tester(?) and it worked great and only cost me $10. I found out what was causing my car to act weird. It was a hose coming out of the intake manifold that had a huge 3-4" tear in it I will attach a pic.

http://i139.photobucket.com/albums/q.../WP_000033.jpg

Also, this is the exhaust that I was planning on buying. Will this suffice?
Greddy 10106802 Euro G2 Cat-Back Exhaust System 1998-2001 Audi A4 1.8T | eBay