I am looking for a B5S4 brake upgrade. Someone is selling a 2001 S4 brake but says HP2. The seller also mentioned there is no carrier needed because HP2 brakes has carriers build-in.

What is HP2 brake? Does it fit on my B6 A4?

 

Never heard of that... Ask the seller how does that eliminate the carrier..

 

He said the carrier is already build-in the calipers so there is no additional (separate) carrier needed. He also metioned it "should be" direct bold-on to B6 A4. That "should be" kind of makes me worry.

Damn... I shouldn't bleed my brake fluid today. The bleed screw was rusted so it just snaped...

 

Yeah, that should be is kind of lame, I wouldn't buy them unless you see an actual picture of the product and how the carriers are built in.

 

This may help a little.
http://www.audiworld.com/news/99/s4_.../content.shtml

Also there is a write-up over on A4Mods.com. Should be direct fit.