Actually for '04 Tamiya is allowing the F201's chassis to be drilled for cooling purposes, but the rule is a little vague, it states "Cutting of the chassis for weight savings is not allowed. However, due to the high heat generated in the motor area, holes may be drilled for heat dissipation around the plastic that encases the motor. Holes may also be drilled to access the tight confines of the electronics wiring. "
I for one would like to get some clarification as to what entails "the plastic that encases the motor".