Some friends and I recently rented some bikes in San Francisco and did an epic trip of Northern California. 2 of the bikes we rented were 2008 GS's. At home my buddy has an 09 GS and I have an 07 GSA. Within 5 minutes of getting on the rentals, I noticed a DRAMATIC power difference between the bikes we ride at home and the rental machines. They also ran smoother and had slighly better gas mileage. In terms of power, the best way to explain, would be to say that when excellerating in 6th gear at 70 mph on the rental feels like mine in 4th! I understand that there is a little more power between 07 and 08 however my buddies 09 really doesnt feel much if any faster than my 07. The only 2 differences I can find in ours vs the rentals are that the rentals have cast wheels and 30-40 K miles and ours have spokes and 6-12 K miles on the odometers. I asked the rental company if they do anything different with maintenance or set up other than by the book and as I expected....Nope. Just a couple of GS's run hard and put away wet. The only thing I can figure is that those rental bikes have loosened up and are running smoother and faster than ours? Anybody ever have or heard of this kind of difference before?