I like it. The Aussies got aabout 135hp out of the Magna with mpi, but that was with a different head with bigger valves. I think you will want a turbo...

I like the flange work. Flame or water cut? How will you plumb the two water outlets? I'd weld a bung on the slot and use a brass nipple for the hot water outlet to the bypass and heater. There is some good plenum sizing info on sdsefi.com in the tech articles. You could weld a hose nipple on the tstat outlet and use a remote bmw tstat housing.

Not responsible for advice not taken...