What have you deleted and why?
 

Here is my list of deletions, totaling about 231lbs so far:

Deleted most power steering hardware.
Deleted back seat and linings.
Deleted trunk linings and spare tire equip.
Deleted stock passenger side mirror.
Deleted 6 CD changer & steel brackets.
Deleted wipers (one under seat).
Deleted rear seat belts, brackets, bolting.
Deleted child seat lock hardware
Deleted rear seat release hardware.
Deleted rear deck molding.
Deleted floormats.
Deleted sunvisors.
Deleted center column moldings and brackets.
Deleted A/C.
Deleted front passenger seat (often reinstalled)...
... numerous other small items.

Some were eliminated for power, some just for weight, some to create the cargo space I wanted, but the center console went because I hated it. Why have you deleted things, if any?

I deleted the mechanical fan on the F150 and never got around to putting an electric one in because it so seldom needs it.

When I run good tires I might delete the spare, if I think of it/if I want to use a giant deep trunk.

The Coupe got a hubcap delete when I blasted and powdercoated the steelies.

Moon Unit got a roof rack crossbar delete, and the rest of it might follow, if it is easily re-installable.

i remember reading a issue of sport compact car in 2000-2001 where they and another magazine where building civic si when they came back the pulled the entire carpet and used a heat gun and scraper and moved all the tarry insulation on the floor if i remember correctly they got between 50-100 pounds but i could be wrong. i also think the left the carpet out.

So far, the VW hood emblem.
why? it killed the cars mileage,kidding,because it did nothing for the car but detract from its character and instill a air of consumerism :p I used a heat gun on a sunny day to remove it, then with some orange spray cleaner and a boat load of effort i cleaned the black tar like adhesive residue off of the hood.

Deleted spare tire - how often do you really need one ? It goes back in on long trips.
Deleted jack and tools - no point carrying these when the spare tire is gone.
Deleted rear floor mats - I hardly ever have passengers in the rear.
Deleted the cargo compartment cover - it reduces the useful height and I usually left it open anyway.
Deleted the container of spare windshield washer fluid I used to carry around.
Deleted the car's manual.
Deleted 1 of 2 high-viz throw overs - 1 is mandatory here.
Deleted the extra cupholders.
Deleted all badges.
Deleted some other small stuff.

For my suburban I have deleted:
3rd row back seat, weighed about 150lb and needed the space for home improvement materials, had the truck since 2006 and never needed that 3rd row.
Belt driven cooling fan, replaced with electrics.
Full size spare tire (another +50lb), but replace when I go on road trips.
factory tire jack (15lb), I just put my small floor jack in the back when I do take the spare tire, I always keep the tire iron handy.
Bug/rock deflector.
A/C but would like to reinstall it if there is room after I do the turbo and water injection install.

Car:
A/C because it wasnt working when I got the car in 2002 and I never used it. The A/C condenser was blocking radiator air flow.
Tire and jack, never had them when I bought it.
Belt driven fan.
Foglights, I needed more air flow up front.
Tested a rear carpet and padding delete, but didn't enjoy all the added road noise so it was reinstalled after I put down a layer of 3M asphalt spray.
I plan on finishing the A/C delete when I get back to the states.
May delete lead acid battery and replace it 2 or 3 parrelled lithium packs used in motorcycles and ATVs, replacing a 35-40lb lead battery with 2 or 3 minipacks that weigh about 5lb each.
Plan on doing a small block chevy engine delete too (replacing it with fuel injected a LS3 serries w/VVT)

nothing.

Funnily enough, on two of the 3 cars, the only thing removed is the urge to hit the redline:turtle:

The 318iS (e36 3 series) is totally stock, and driven daily by the Burd

The 320i (e30 3series) has been lowered but nothing removed
The 535i Track car has had

Interior
Boot Trim
Bonnet Trim
Spare Wheel
Foglamps

Removed for use on track.

I'm thinking of trying to come up with a way to remove 100kg from the 318iS and the 320i that DOESNT affect the look, fit or finish of the car..
anyone any ideas?

That is a bit of a tall order, first thing that comes to mind is replacing the rear glass and back windows (if you have them) with lexan. You can replace the wind screen and front windows but there are saftey risks that go along with doing this.
Replace the hood and boot lid with stock looking fiberglass or carbon fiber replacements and have them painted to match.
I don't think all that would quite get you to -100kg but would be a good start.

Deleted - rear badge
Deleted - Some start up fueling
Deleted - Front plate and bracket I hate the looks and it is not required