I've noticed online has been suffering lag a lot more recently, it was woeful for me at the last weekends Avalon meet, and it's not just the analog that is suffering as I use the D-Pad and remap my air brakes to L1R1
I was constantly scraping walls on tracks that I could probably perfect lap with my eyes closed due to steering problems.
I'm not sure what the cause is, but I suspect it's something to do with the amount of new people playing, if being a +subscriber is part of the cause I don't know, other online games have been suffering some glitch's that have been blamed on +subscription from what I've been reading at PS forums.
LBP most notably.
It seems to be games that have been given away with + subscription.