A lot of other scoot owners have had good results with one like this..
http://www.harborfreight.com/12-volt...nch-92349.html
If the description is accurate, it is powerful enough to strip any fastener on your scooter, so I would go easy when using one.
I use an air powered impact, mainly because I have the system left over from my working years, and the fact that I still have 11 vehicles to maintain....from the scooter to a diesel powered utility tractor. If I had only a scooter and a car....I'd probably have something like the one I linked.