I don't have the ET but do have the EB so maybe someone with the ET can add to this.
Both share the same chassis and battery tray which is designed for a standard 2S shorty.
Weight is going to vary with either being dependent on all the other things needed to complete the kit. Electronics, battery, wheels, tires even paint and stickers add up. Mine ready to run less battery is 1674 grams.
Wheelbase and track width have tuning options for both kits. My wheel base is 285mm with front and rear track at 237mm and 217mm respectively to the outside of the hexes.