Well, I've been a long time reader but I had to sign up to reply to this one, I've built a few safari race cars, and I can tell you right now that not only do they twist a fair way (although not 3 full revolutions
), that yes, we do also want them to twist, in fact we usually make them out of tempered spring steel with oversized splines and waisted centre sections specifically so they are as small diameter as possible for the strength needed.
Because they're a spring they absorb the shock loadings in the drivetrain meaning the gearbox and clutch can be designed to cope with lower peak loadings, they also help to prevent overloading the tyres on the rough sections.
The calculations before as someone has said are wrong because of the multiplication ratio from the geartrain, should be around 13-14 times higher in first or so, but I would expect the highest shock loadings would not actually come from the start, but rather from riding rough curbs with the power on out of the slower corners as the tyre loads and unloads, the shock as the tyre briefly spins up and then grips (even with a lsd in the back), would probably be much harsher than the start is.
FWIW, the driveshafts we use generally have maximum twist angles in service of between 38-48*, depending upon application.