It looks like they've cut away the front bulkhead for the centre driveshaft to fit above the standard mk1 steering rack. Boxed the tunnel in at the front. then probably ran it inside the original tunnel to the back of the car. they've had to mount the gear shifter inside the car to clear up the tunnel for the shaft. Also if you look at the lower arms. it looks like they've had to raise the height of the inside pivot points on the lower arms because of the height that the centre shaft has been fitted. They might just be beefed up, its hard to tell. Doesn't look like theyve fitted a subframe from a later car. That is a superb! I love the way it takes off!