Although the Scorpion is a wicked engine in looks and performance, it was mostly a sales flop. Mercury has since discontinued production of the engine. This will affect your resale down the road, and they were unbelieveably expensive in the first place, rivalling the cost of an HP500EFI. I am not 100% sure, but I think they require 93 octane due to their compression ratio as well.
If it were me, I would steer clear of them.