Thanks for the numbers! I actually had my car apart recently but had forgot to weigh the aluminum plate.
Using all stock parts, a liteweight body, and "typical" electronics my car weighed just a bit over 1380 (without adding weight). The car was balanced due to proper placement of the electronics.
I replaced all the steel screws for the upper deck, shock towers, swaybars, a few random pieces, and bumper with aluminum ones..... It shaved about 20g without effecting performance or durability. I ended up adding the 20g centerline on the chassis plate.... The car already has a low CG but I noticed a small difference on the track dropping it even further with that amount of weight. It is by no means necessary to change the screws, but if you have them available or need to cut weight it is worth doing.