Uh, you do know that the late interiors are not a direct swap, right? The rear seat belt sockets are different (the '87 body lacks the mounting holes for the late style sockets), and the V8 front seat frames have different bolt spacing, not to mention totally different electrical connections. You'll need to keep your '87 seat frames/motors and swap on the E420 cushions + backrest. Can't swap B-pillar or C-pillar trim either. I already went through this drill when I installed an E500 interior into my 1987 300D. The heated seats were worth it though. The door panels are about the only thing that is a direct swap...