Yeah the mk6 Bilsteins fit straight on, same fitment and axle weights etc but the mk6 version has been revalved to be around 20% (iirc) softer due to customer feedback on the harshness of the mk5 version,
I tried a car with the mk5 setup and just found it a bit too firm for my daily drive and the poor roads round here, not had chance to try a car fitted with the mk6 setup yet but the feedback from those that have them is superb
Bilstein normally get it spot on first time with any setup, but the fact they have softened the mk6 version for an identical chassis setup shows they may have over egged the pudding a touch with the mk5 version?
Saying that those that have them seem to love them and it's undoubtedly a fantastic setup, just too firm imo for a daily especially when combined with my H&R arbs