I ran across this problem a while back when my MKIV twins had the beginnings of the death whine. All i would hear was whine, whine, whine on the first turbo and boost pressure was not optimum and consistent. When i looked i could not find anyone with the tools and expertise to do it. Closest i found was a company in Texas. I ended up getting a low mileage set to b/c the cost was substantially cheaper than a rebuild @ like $700+ for both turbos. Been using my used set for quite a while.....GL