Looking at the overall weight of the thing, the wheels and hubs would be the heaviest part of that car. Followed by the engine and transmission, then the rollcage. I'd be curious to find out how much it actually weighs (I think it'd be around 900-1000kg's)
I also wonder why nobody builds track based vehicles for that kinda thing actually.... I know of some armoured vehicles that could easily traverse one of two of those obstacles, and do it without thrashing around like that crawler does.
Also, knowing that electric engines are 'the new way' we're going to drive vehicles (it'll eventually be the way for those rock crawlers too) it makes me sad knowing that 'the number is up' on engines that sound like that :(
Toll, that's an awesome call (on the helmet bit). Even in that compilation you see the driver complaining about getting smashed by debris while driving it..... what a squeezer.