http://www.supercar-engineering.com/.../Mods/TT/CFDS/
Erik Gross was one of the first to document the vibration problems with the 2-Piece setup. As I said before though, PST has since fixed this problem (at least to my knowledge).
And thanks for the info on the one-piece system. But does there seem to be a trend to the vibrations? (ie. 5-Speed or 6-Speed, build-date, brackets or braces on the transfer case, aftermarket rear LSD) I'd like to get the 1-piece since that would obviously be lighter and put more power through to the wheels, but I'm not going that route if it'll just end up killing my car.