there is so much more than just bulkhead mods that have been excluded, the cat 3 log book will allow this but there are measurements for the height of the tunnel, the width, and the distance from the floor and from the sills all have to comply, you have to list all your engine components, brake disc make/diameter/thickness, suspension design/make dimensions, its ridiculous really, but this is why they have done it, simply, you must all comply to this approval, or you dont do it. thats the MSA for you.