i bought the car with manual mirrors, manual windows, manual locks, and manual steering. then:

-i took out the entire airconditioning system(i.e. condensor, radiator, pump, and all plumbing)(40lbs???)
-no spare(20lbs)/jack(5lbs)/basic ratchet set(11lbs) for local driving
-front bumper support(7ishlbs)
-driver side front tow hook(1-2lbs)
-lawn mower battery (12 lbs) in leu of stock (35lbs)
-antenna block(1lb)
-hx rims(12lbs) with falken ziex tires(17lbs)
-apexi ws2 exhuast (the muffler is like 5lbs less than stock)
-keeping the interior clean is worth its weight in gold
-aftermarket junk aluminum hood is 8-10lbs lighter than hondas stock hood.
-no interior hatch cover(i never knew how much it weighed...)
-aftermarket header(12lbs less)
-aftermarket intake(5lbs less)
-center rear seat belt(1.5lbs)
-floor mats(5lbs)

unfortunately a good portion of this weight reduction is negated by the addition of front and rear swaybars(7-10lbs each) and foglights(3-4lbs each). also even with the full interior i think the car is too loud from road noise, so i put insulation behind the rear interior panels and behind the door panels

jolt: why did you take out the rear torque mount??? you dont like traction??

The back seat doesn't weigh much the seat belts and seat belt hardware is where most of that is from. I know the passenger seat and it's belt is heavier but sometimes you have to keep things for reasons other than efficency. Also I planned on putting fiberglass bucket seats and a 5 point harness in the front, more stuff left over from old project cars I can re-use.

There is a lot of that asphalt type soundproofing stuff in the car. I would recommend that if you have the seats out for any reason go ahead and pull the carpet out and scrape it off. I found huge amounts of rust under it where it trapped water against the metal. There was enough rust that I am just about ready to abandon fixing up this car and trying to swap the drivetrain into something else because the unibody is almost rusted in two on the drivers side. I would say get that junk off the metal as soon as you can to keep it from rusting out the floor. A hammer and flat screwdriver gets it off pretty fast. It might take 2 hours total to get every bit of it off the floor. Then a few quick coats of rust inhibitor on the metal. While it is drying you can scrape off the soundproofing from the carpet with a 3 inch medium putty knife or something similar. I also hung up the carpet and pressure washed it to make it look like new again but that step is optional.

But anyway as far as the weight it makes a huge difference on hills. I got reminded of how much better it is when I had a friend in the car with me going somewhere on a hill I normally drive my commute on and I had to downshift going up the hill when I can normally pull 5th all the way up. I figure the easier acceleration and better handling from doing weight reduction is worth it even if it doesn't help mileage much. Taking the seats and carpet out of a metro is like a 30 minute job so there is really nothing hard doing weight reduction on them.

The car is light enough that one person can pick up a front tire off the ground and I can lift the entire back end off the ground. I figure I will pick up 4 bathroom scales and weigh the car sometime. With the car this light it is very easy to parallel park though, just drive the front end in and get out and push the back sideways into place. You can park it in otherwise unusable spots and also get it back out pretty easy.

the truth about weight reduction is this:

there are about 3-4 things that take out 30-40lbs and 100 things that take out 1-2lbs.

so if you take out your spare and jack, gut the rear seats and take out the airconditioning you are almost halfway through.

I had a brain fart when I typed that. It was the intake manifold mount, not engine mount. All my motor mounts have been made solid polyurethane :p

I took out the jack, spare and tools, then replaced it with a can of Insta-flate tire sealer/inflater. A towing clause in my insurance takes care of the back up plan.

I also removed
rear seats
rear seatbelts
plastic body work and rugs inside the rear hatch
heat shields in the center tunnel and near the muffler (also aids aerodynamics)
smaller battery
lighter wheels from an Eagle Talon
rear wiper arm and motor during summer
engine balance shafts- also reduces parasitic losses and raises oil pressure, so lighter weight oil can be used.
There might be some other little things I'm forgetting.
Then I added about 15 pounds with a front mount intercooler and 2.5" piping. :) It more than pulls it's own weight

aaahhh ok yea i have done the same things. i forget about half of the small weight reduction things ive done.... i edited that post like 4 times.

the rattle from the stiffer mounts gets annoying but thats just because its my daily driver.