I cannot help on the alternator front but the inlet manifold from msd does fit in a lhd car. We have a customer in holland with one in his lhd sierra sapphire cosworth.

I personally do not like the atb and prefer a plated diff, gripper from bars or speak with mike rainbird about a Titan unit which I have in my own car (although it's not on the road yet)

All these units go into the standard casings and I would advice 7.5" unit being 2wd

Hope that helps a little

Jim