Classic and worlds RC10 re-release

[Mash Potato]

I bought a classic kit as soon as they came out with the intention of one day racing it. Now I'm not too sure if I was a bit too hasty, as having seen the worlds kit maybe I should have bought that instead.

Lets say I were to stay with the six gear box (is fitting a stealth even an option, does it fit the classic chassis?), what else is actually different and worth getting from the worlds car if I were to upgrade my classic?

What are the differences between the two chassis's? I know the world is milled, is this purely a weight saving effort, or is it for another purpose? I can see the advantage in the old days of NIMH cells, but with Lipo's surely it's pretty pointless?

I'm basically trying to decide if I should upgrade my Classic, or stick it on the shelf to look pretty and get a worlds instead.