the weather and amount of fuel on board will have a slight roll to play in how quick the car is, but not that much that it would be physically noticeable when just driving around normally, more applies to the race track!! i replaced my D.V last night on my GTI (non ed 30). it had the revision b version. The one ive fitted is the revision d. The symptoms my car had were very little acceleration above 3000 rpm, and a hissing noise, which was the air escaping out of the split in the D.V i imagine.