Below is what I did with mine. The alloy was either 2.5 or 3mm and was sourced from an old car audio amplifier (it says pioneer on the bottom). Because it was so thick, it was very heavy so I used a large drill and starting drilling the metal out on the top. This saved heaps of weight and it is still impossible to bend. The complete finished buggy is 18grams heavier than the standard truck.
The custom chassis is soooo so so much better than stock. It sits flat over every jump, and corners fantastically. When I raced it against guys with 18Ts and Mini-T Pros, it was able to out corner all of them.
All it needs now is a set of a narrower front wheels and it will be perfect.