I've removed 278lbs (conservative measurement) from my Gen4 DOHC.
-Carpet w/ insulation weighs 30lbs
-Rear Seat and Seat back 35lbs
-Passenger Seat 45lbs
-trunk latch + hinges=10lbs
-spare tire w jack 45lbs
I dont remember weights on the rest of this stuff but it accounted for 118 lbs...