Sorry for an old thread bump. I don't care about nitrogen, but I am interested to hear from anyone that has had experience of both PS4 and Primacy 4 tyres (ideally on the same car). I'll be needing a set of tyres soon (for a 2014 A3 saloon) and was going to go with the PS4, but since I'm not a hard driver anymore; I don't attack corners or power out of bends - I generally waft around at normal traffic speeds and occasionally get my foot down in the country lanes when it's clear - I could trade a bit of out-and-out grip (I never find the limit anyway, so I have a big buffer) for a bit a more comfortable, quieter ride, and maybe a little mpg gain if poss.
