Where and how much more are you thinkin could be shed?
I'll throw my $0.02, if you replace all the aluminum chassis parts with CF parts (C3 is tooling up to do the bulkhead pieces soon), tunnel sides and top, entire over structure including the cast connectors, the bearing plate in CF with Titanium bearing bores, CF drive shaft with Titanium splined ends, Titanium steering post, Titanium pitman arm, and Titanium idler arm, Titanium A-arms if CF proves too fragile, CF version of the EZ-Ryde with CF Rails, smaller aluminum Ceramic brake disc located on the drive shaft under the driven clutch, CF plastics, CF fuel and oil tanks, CF air box, CF belt guard, CF handle bars, get rid of all the needless steel brackets (I.e. The front seat clip, exhaust brackets), Hydro-Phobic hard anodized Aluminum bumpers, all bolts replaced with either Titanium or hard anodized aircraft aluminum hardware where applicable, ceramic hybrid bearings thru out ( crank shaft included), Titanium or ultra thin inconel exhaust, quality aluminum tie rod ends, no zerks ( Delrin bushings throughout, assembled with a thin film of light arctic grease), minimize the needless electrical components, LED lights, etc. etc. Everything scrutinized and weight saved, all while fixing the weak points that the consumers have identified.
Another 100#'s easy! Not cheap, but easy.