I have a 2006 7.5, it's my 'go to' bike. The one thing that I always wished for was a carbon fiber fork, to soften the ride a bit. I get a lot of road vibration up through the handle bars. That is until this last winter when I put on carbon bars and stem. What a world of difference it makes! They really dampen the vibration, and make the ride much more comfortable. It's was noticable on the first ride.
Other than putting on 25mm tires, no other real upgrades.