I would not recommend Vortex from my experience. I did the -1/+2 mod and used Vortex for the front sprocket. After only 1 year and 3,000 miles I started noticing a lot of driveline lash. I replaced the cush drive rubbers which helped, but there was still too much lash with the chain adjusted...
Don't know if anyone else here has had this happen, but just thought I would share in case you have similar symptoms. I have an 04 FZ6 that now has over 11k miles. Never had issues with starting other than battery, but that was to be expected with a 6 yr old battery. So with new battery...