| Ask Guido on this forum.
He had some special bungi made that mount on the engine mounting point (you need to change the battery for the small model - actually you probably have that one already on your bike). This is just about as tough as you can get with no risk to the frame since the engine acts as a stressed member.
R&G and other Moko crash mushrooms mount on the frame which would indeed potentially bend it as a result of an off.
Also Guido's solution is mounting slightly lower than RG & Moko so I would assume that the bike balances better and this will give better protection to water pump and clutch.
I will put my order in soon Guido, just need to sort out of few things at the moment... | 
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