true, you can add lowering bases if desired though and are model specific.all of the aftermarket seats ive come across use the factory seat base.
I would still like to see this set up if possibleon mine it looks like the guy just notched the frame where the seats bolt down and put to steel rods at a slant and bolted the seats to that, so they dont sit straight up they kinda recline and sit lower in the butt area