This modification removes the stock decklid hinge boxes and uses modified hinges that bolt directly to the chassis tube under the rear glass. When doing many engine swaps, the passenger side hinge box interferes with the new engine. Instead of cutting/notching the hinge box, this mod completely eliminates them for a smoother firewall look.

Again, this modification requires removal of the stock hinge boxes (lots of cutting and drilling out spot welds), so it won't be for everyone, but I like the look of the mostly hidden hinges - especially when used with a smooth firewall panel.