Total loss electrical system would lighten it up some. All the BHP aint gonna do crapoli if the bike dont handle. If you took 2 bone stock F3s with the same tires, take one and do nothing but horsepower mods (naturally aspirated of course) and the other do nothing but suspension mods, the bike with the suspension mods would do quicker lap times. Unless you were racing on the autobahn, maybe.

 

definitely try to source some aftermarket cams, had the head on my old f3 ported and polished and the crank lightened and balanced. she rev'd quicker, but there were no real power gains since i kept the stock cams.
but like coalminer said, invest in your suspension. you dont need a fox or ohlins shock. just get the oem one revalved and sprung for your weight, as well as the forks.

as for weight savings, you could probably cut off the back half of the subframe and make it work with race bodywork. but since its welded on, replacing it with an alloy subframe would be difficult to do it properly.
but definitely read through those two threads i linked to, he goes above and beyond for weight savings.