Modern seats and shoulder belts

I don't have any pics to show right now, but I'm using BMW M3 convertible seats in the front. They're power, have good lateral support, have a convenient flip forward set up, and most importantly they have the shoulder belt integrated into the seat. I made a frame under the car that is welded to my subframe connectors to deal with the shoulder belt being part of the seat. For the rear passengers, I am working on reinforcing the C pillar to mount the upper shoulder belt to. The inertia reel will be mounted behind the interior panel, and the seat belt will come thru the panel near the top, more like a modern car