MK5s don't have weight balanced driveshafts from the factory. Certain older VWs had weighted rubber discs bonded to the longer shaft, which was a harmonic absorber, and it often fell off or came loose.
Good call though, the spline wear mentioned is spot on.
FWIW, I had to replace an outer CV recently and at 125K miles, I wasn't sure of the integrity of the inner joints either. Long story short, I got a sizeable discount on a pair of shafts from VW, complete with new CVs at each end, ready to throw on. It worked out more cost effective than replacing the individual joints, and I hate getting that hideous moly grease all over the place. A lot of the 'heavy metal' parts have much bigger discount codes than the smaller stuff, you just have to ask. They won't tell you that off the bat, obviously.