Technically you should follow the VW specs (504/507? 505.2? I forget). If you ask this question on VWVORTEX they will tell you to pick a VW cert oil and not "take chances". There is an offical list around here somewhere. It includes Pentosyn, Motul, Total, Castrol, M1 and a few others. Many of the oils are tough to find locally (except the M1 and Syntec).
But I have your exact car and am on my 4th OCI using RP 5W40. The car really seems to like this oil and the UOAs (I posted one a while back) are good. Royal Purple does not have the VW cert but the specs are right in there. At 5K the TBN was low but still fine. I tend to change at 5K and have not tried the 10-12K OCIs some folks run.
*edit - Ah - here it is: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1631685#Post1631685
VW does say synth and their pref is 0-5W40 with 5W30 as an alternative if you can't find xW40.
I've run M1 in this grade as well and it was fine. I wouldn't hesitate to run GC. Anything on the VW list is good oil. Most dealers seem to use Castrol Syntec 5W40 FYI.