Few ounces would not hinder the truck's speed.

a few ounces to a racer (what it was intended and designed for primarily) is like a couple of pounds to a basher.

Also if the chassis is hevier the truck will have more momentum and be more likely to break when it hits something

Well, if it comes for racing, then I think you're right about what you say, but still, 2 mm is a bit weak for a monster truck.

But the DESIGN is what keeps it strong.

Sure. Only the battery trays and few other parts were made out of CF, but in a hard crash, if the hit was received by these parts, I imagine it would be painful. The FLM chassis is good, but not as well designed as the G-Maxx chassis or the Lightning. If I only can get a Lightning chassis, I would not be complaining, they're out of stock, as far as I know. Well, back to filing more aluminum....