I recently changed the vario, belt and clutchsprings on my Xciting 500 (2006) with Malossi parts
It changes your scoot dramatically I think. Completely different ride.
The trick is that the engine revs up to 7000 rpm's almost instantly and makes you take off very fast. I also had the clutchsprings changed to the stiffer white ones Malossi offers.
The good thing is that Rpm's are NEVER above 7000 rpm's; it'll never go in the red. Malossi did a great job on that I think.
The top-end is just slightly (!) lower. I clocked it about 155 km p/h.
Don't notice any change in gpm.
I love the new setup. Had it on my Burgman 400 also for about 15.000 miles, so I knew what it would do to the Xciting 500.
It's much more responsive and few bikes can keep up with you now at traffic-lights
The Dr. Pulley sliding weights (2822) are for sale. They work fine and are a very cheap and effective solution for those who seek more acceleration, but this new setup is just better.
The sliding weights were used for about 500 miles. Let me know if you are interested.