I've had the ROTAX 40 amp kit setup for about 1,200 hours. No issues with it. It's even been submerged overnight in the Columbia River.
If you decide to go this way, I would suggest drilling and safety wiring the upper pivot bolt. The clearance between the hex head and the belt is minimal. If it backs out, you will smell burning rubber in the cockpit followed by a destroyed belt. Don't ask how I know.