The rotary is a great motor and was invented by a German named Wankle. This is actually the best motor for a conversion. It's small and makes insane power.
shiwlof, that's the motor you sould use for a rear engine design and it fits in the Bug's bay like it were made for it.
Vincent, if you're going all out
go for AWD/4WD
humm, a mid-engine W8 with AWD on a 1303