The bolt ons are usually stronger too, because it has to support itself when opened. Many times, lift off parts are a basic skin and no structural strength so they are for racing only. That's why the bolt on costs more, so you can bolt it on like a stocker. A lift off requires fasteners like Dzus which also means welding in the secure tabs for the fasteners. The stock hatch latch isn't able to be used with a lift off lid, and you'll have those fasteners visible around the edge of the lid. That also means no key or lock...