Moroso Battery Box in trunk. The Independent Rear Suspension adds 75 lbs to the weight of the car, but it removes 125 lbs of unsprung weight. The coil overs also significantly reduce unsprung weight as well as overall weight . While I did not weigh the factory springs and the HyperCoil springs. I would guesstimate they represent about a 50% weight savings over the stock pieces, I'm thinking 35-40 lbs. So I may have only gained 35-40 lbs overall with 75lbs directly over the rear wheels. The battery moves another 60lbs over the right rear wheel.  That's it for now...next spring Brembo's, 18.5 Cobra R rims and Toyo TS1's