I've found a source of some quality low weight 1 and 2 piece rotors. I'm trying to findout if the weight loss in the aftermarket rotors in worth the price.
I'm sure you know that rotating weight has more of an impact than static weight, so what better place to lose some weight than the rotors... espessialy since using DWB means I hardly (if ever use the brakes)
My brembo black rotors that fit the insight (same as 1984-1987 CRX Si rotors) weigh 8 lbs, I just weighed them.
I you want to save weight on your car the rear hatch is a good candidate. If You want to be convinced remove the gas springs in the rear hatch then try to lift the hatch
Making a carbon fiber or even a fiberglass hatch with 2 simple lexan rear windows can you save you significant weight. Just keep in mind the heavy and strong rear hatch is part of the safety structure for impact protection during a severe collision.
Going on a diet and losing a few lbs is probably the healthiest and safest way to reduce weight in Insight. It's obvious Honda looked at everything in terms of weight reduction during the development of the Insight.
A huge weight savings can be achieved by keeping the tank 1/2 filled or less. I think it's 8.xx lbs per gallon (correct me if I'm wrong) My tank average always goes up on the last 4 gallons, but personally I do prefer the twice per month fill ups. I'd bet with your set up and 3 gallons of gas, you'd get pretty far.