IMHO, the cage does more than protect and look scale. One of the inherent problems with the original Losi Heavy Metal XX4 body, and to a lesser degree the Slash is the parachute effect. With the back of the body cut out for the cage to be shown, it allows the air to flow freely, therefore giving the truck (again, IMHO) better flight dynamics.
Truth be told, only time will tell. Lets see some on a supercross style track gettin' some air.
--Joey -- AtomikRC/Venom Batteries
Old School Racer, Vintage RC Car nut
AE: RC10 (X4),B2,B3,B4 worlds,B5,B5M,RC10T,T2,T3,T4,T5M,B44.3,SC10
BSR BZ-444 pro,TRX3,MK1 Kyosho Ultima