It takes patience to strip the car to that. I've done it with a Celica when my friend wanted to add extra sound proofing, we did it together in a few days, and had a garage to keep all the parts. I would feel it is possible to strip half the car and lift up only 1 side of the carpet if you need them. Their presence would definitely be felt, we had a car PC installed and cables running under his rear seats and you can actually feel the cables when sitting on them (VGA, USBs, power cables, on off switch cable).
I Saw 50: I was just looking at your pictures, the shifter knob should actually twist out and the cloth cover would be free to be removed totally (if they are the same as the Celica).