I think you can make simple mods for seat mounting, IIRC. Read the good book to be sure.
Not sure how comprehensive your "NASCAR" bars are. They only NEED to be any kind of bar that protrudes into the door cavity to qualify for gutting the door and the door interior panel. Don't go overboard here. I've seen insane setups with a gazilion bars and gussets get t-boned....and the driver still got injured because the whole setup was attached to the roll hoop which was attached only at the floor location. Those door bars could have been eliminated nearly completely, and a transfer bar added and the result would have been safer AND lighter.
Concentrate on the front. I imagine thats where the weight savings will make the most difference.
Hollow sway bars? The solid ones weigh a ton. Camber plates aluminum? The steel slabs are heavy, high up, and in the front.
sometimes cars have oversized radiators. Remember, it's not just the radiator, it's the coolant that weighs as well.
Some of those intake tubes weigh a ton, and sink heat INTO the incoming air. Aluminum is a GREAT heat sink...
If you are running an airdam and splitter, look there as well.
And tires. Look at weights of tires. Hoosiers are known for being light. As mentioned above, thats a triple benefit...less unsprung weight less static weight and less rotating mass.
There's even possible weight to be saved in the dampers....
Divers seats can vary greatly.
Headlights: plastic lenses instead of glass.