Shift knob...
#7
carpet weighs about 50lbs and i think it saves like 1/8 of a second on the track...plus every little weight reduction may not be much but a bunch of little things add up ya know
#10
50lbs? I dunno about that... I just replaced my carpet in my car and it sure wasn't 50lbs. But whatever floats your boat you know? I'm a guy that likes my cars having carpet cause I feel it's more comfortable. You probably feel it's more comfortable without carpet.