The golf R32 engine has intrigued me, I haven't done any real research, so it's probably a garbage idea for some reason, and is probably not ideal for high rpm, but from a capacity vs physical size, it could be alright...
it seems like a likely candidate for a +t conversion, just check out the head gasket surface area between the bores, and the number of head studs.. (2 things not easily changed on an engine)