there are still pretty many things out there that you can do, just a few are.....
cuttin out the center of the front belt bulkhead thing, not really sure wat its called.
more graphite parts.....front bumper plate, receiver battery plate,
steering plate, lower suspension mounts, lightweight upper deck,
brake pad side plates.
carbon graphite suspension arms set. hpi part
lightweight engine mounts
and if u really want, use a li-poly battery for you reciever.
i hope i gave u a few ideas...most of the stuff is found at www.rcmart.com