The weight difference between the composite and graphite isnt much. My composite chassis weighs 172 grams bare and my graphite chassis is 155 grams. Thats not much considering my graphite chassis is extensively milled out (battery mod, motor area opened up and lightening holes at both ends). The big advantage to the graphite chassis is the stiffness of it on carpet you will notice the difference alot compared to the composite. When I build a new car I am going with the BMI Chassis
. For all of the time I spent cutting and milling my graphite chassis. It would have been easier and cheaper to get a BMI. Plus the BMI is stiffer than any stock chassis could ever be. For carpet you want the stiffest setup you can get compared to asphalt where a little chassis flex is desireable.