The insulation doesn't really weigh that much though as a whole even, and I don't even know what parts you could remove that aren't necessary or vital for not crumpling into a ball in a wreck. I guess if you were going to do it by little bits you could include all the carpet padding with the spare tire, the trim in the trunk, seats if you don't want them, spare tire and that crappy scissor jack, you could figure out a way to remove the engine maintenance hooks if you relocate some grounds. Also, there's a metal bracket under the battery on the transaxle on mine that's totally unnecessary. You could delete the exhaust heat shield in exchange for header wrap, delete the air conditioner if you're an extremist along with cruise control. though I don't suggest you do this you could skeletonize the hood frame with a small hole saw and the trunk lid, you'd just have to be careful not to hit the skin of the hood and prep and paint the holes to keep them from rusting, and you'd have to be careful opening and closing them. Beyond that I've got nothing, and without deleting the seats you probably only saved less than 200 pounds doing that.