If you want a "lighter" chassis then you should ask troy.. He has the tooling to make it happen! Hint hint buddy!!!
And to me 50 grams isn't that much in offroad world compared to onroad. I had a 22 since they came out and Im a new daddy to an rb6. Yes its chunky but love the way it drives compared to the losi. Plus having the pro kyosho guys locally sure does help for set up and setting the bar