I have an S5 GXL with a sunroof. I really like having a sunroof, but I would also like to get the increased head-room of a non-sunroof car. I noticed that first gen RX-7's have manual flip up glass moonroofs, which I am assuming don't requre the entire lower assembly/rack/motor of my current sunroof. Is it possible to remove the entire sunroof assembly from my FC and replace it with an FB unit? If it is possible, will the result actually be increased head-room?