does weight affect performance much? and is alloy heavier ior not? say a half alloy, half plastic truck, would that be slower or faster than a all plastic? (ofcourse diffs and stuff would be alloy)
cheers

Yes of course weight makes a difference.

Alluminium and any other metal WILL weigh the truck down and therefore make it slower. If you read the race forums you will see that everybody who races anything, wants it to be lighter.

Heavier trucks CAN be more robust, but, not neccessarily.

The only parts I would have metal are things like gearbox housings and bulkheads to remove the 'play' from the driveline.

Weight makes a difference. I usually need to be drunk to consider hooking up with the gravitationally challenged. OOps.

if your looking into racing more than bashing get CF tvps n shock towers because that will lower yoru weight but if your more into bashing get soemthing that is strong n isnt likely to brake.