I put a 2 seater rear shroud (from a 6 cylinder car) on a BT7. You should purchase a "Rear shroud support cockpit side" made by Kilmartin - part # AH487. The cost is around $400 through British Car Specialists. The is an add-on and you can use rivets instead of welding it in if you decide to change it back, sell the car, or whatever. I used rivets because if, or when, I sell the car I can easily remove the support kit and put the original 4 seater shroud back on it if a "purist" were to buy it. Other than adding the support kit, there are no modifications that you need to make to install a 2 seater shroud. Again, this info is only valid for the 6 cylinder cars. I believe the 100/4 shrouds have many differences from the later cars.