The only thing that would be a problem is the reduced rotational mass of the drivetrain. The weight of the flywheel is a factor in getting the buggy moving. If you have a heavier flywheel it is easier to keep the buggy moving quickly and the engine doesn't have to work as hard to keep the buggy moving. A lighter flywheel will help the engine to hit higher revs more quickly, but will make it tougher on the engine to keep the buggy rolling and put a little more stress on the engine from the buggy itself. This is especially true after catching some air. When the buggy lands it will put immediate stress on the engine to get the buggy going again with a light flywheel, whereas if you have a heavier one, it will be easier to keep the buggy going after the landing and reduce shock and stress on the engine.