We got the Solar sunroof with the electric rear sunshade and manual rear sunshades as an option but no dual pane windows here, not until the C6. A lightweight Odyssey battery (PC925T) will save another 39lbs and as mentioned, Forged wheels (my BBS RS-GT's in 19" are 15lbs per wheel lighter than the stock 18" wheels), spare tire, dump the extra aux radiators and plumbing. The battery and spare tire take weight off the back of the car which is where we least need to remove weight but I think most would agree any removal is better than nothing, at least in a way that doesn't detract from the original looks or design too much. Wheels and Radiators probably help the most (as far as handling goes) but Forged Wheels are a chunk o money.