James,
I can't see anything wrong with stuffing an M44 into your car, but I'm not an SCCA rulemaker, so I would want a ruling before I did it.
Yes, the windshield and frame are gone. Tony Rivera built a slick asymmetrical cage in it, penetrated the firewall and connected the low front hoop to the front strut towers.
I have used the passenger area for fuel cell (inside a custom aluminum box to meet the bulkhead requirement), battery, and fire bottle.
As to the motor, if I get the car trackable for this summer, I will be running stock with Electromotive Tech 3r, no power steering pump, and an underdrive pulley on the alternator.
I guess it depends on how competitive you want to be and how quickly you want to get there. I'm content to develop the motor in stages.
When we build it, I'm going to see what happens using the stock FI rather than the Webers. I've been told that the stock crank is very strong, so first step will just be rods and 12:1 pistons.
Don't know where the weight is, will weigh it in a few weeks.
Joe