What I meant is that I don't think there is another manufacturer option other than Rotax. Then within their power line, only the 582 has the hp/weight ratio that works on the 2-place Quicksilvers.
But again, consult Gene "Bever" Borne. I've been flying Quicksilver products since the 70s. Bever has a reputation among Quicksilver owners as being both the most knowledgable and most helpful person on the Quicksilver product on the globe. He is, in the opinion of every Quicksilver owner I know, THE source on Quicksilver information.
-Buzz