Parts listed at bottom.

Plastic container that can fit in BHW air intake: 2.8-in min, 3.2" max. Cork size used for small tube was 1/2"-0.75"in.

When/if you do a boost test, try to use the maximum PSI your turbo generates if possible, as it will help you find any leaks that occur in the real world. In my case I used 15psi. MAKE SURE you put your retaining clips on EXACTLY same way they were on (same direction) or your hose will likely pop off and you risk losing a clip.


PARTS
I'm not affiliated with McMaster-Carr in any way, nor do I get a kickback. If you can purchase the original O-ring seals from VW/Audi, I think that'd be best. The o-ring I used was mcMaster part 1295N639, but you can see that it has a 42mm ID and 5mm thickness which resulted me me having to sand it down to a thickness of 3.7mm before I could squeeze it (while on the intercooler fitting) into the turbo. If I did this job over (replacing the oring on the hose that plugs into the bottom end of the turbo (the exit, boosting into engine), I would try my luck with Mcmaster 1295N639 (knowing that 1295N639 might be a bit on the large size and may need to be sanded), or try 1295N591, knowing that it's thickness is 0.138-in, and I found a thickness of 0.146" to be about perfect, although actually very difficult to get in. I think the 1295N591 is most appropriate. I used silicone grease (same thing as "brake grease") to lubricate the o-ring during installation.