I too am a fan of the MGFMania glass rear screen. Not only can you see out of the rear and can demist, I think it add class to the look of the car.
Looking at the photo of your cracked screen you do seem to be missing the 'parcel' shelf cover (hood well). I've dispensed with the massive sound deadening as I got fed-up fighting it everytime I wanted to remove the engine cover but I have peeled off the top layer to use as a liner as it cushions the blow a bit when the hood is lowered which is quite important if you go 'glass'.
Richard
1.8i Mk2 Solar Red, 16 inch square spoke wheels, MGFMania hood with zip-in glass rear window, DRLs, Kmaps ECU, Pipercross panel air filter, MGOC Supersports back box & some cockpit bling