At this point in time it shouldn't need an SVA if it is using the chassis from the beetle (I'm not sure what happens if you start altering the chassis though, ie stretching it)
There are plans afoot to bring modified cars into the SVA scheme though so you might want to get a move on
just in case. Can't remember where I saw details of this but it is being objected to by the hot rodding association.
Cheers, John