I have a harness (3 point) though one of my points is where the back seat used to be. With back seat in, you either have to mount on top of the rear deck, or to the C-pillar (and of course lower bolts, go in floor pan or I think some can go on seat frame). You can also get a custom roll cage (or half roll cage) made and mount to it. My harness is a corbeau double release, snap-in 3 point.
