If you are looking to upgrade your drive-train for off season competitions, I would suggest this gearbox that andymark sells:
http://www.andymark.com/product-p/am-14u-tc.htm
The gearbox has the same hole pattern as the ToughBox mini and only costs 150 bucks!! Our team changed a reduction in order to achieve 13 fps instead of whatever came standard.
Team 4476 used this gearbox for the entire Arial Assist season and couldn't be happier with the gearbox.