My two cents on the topic of number of wheels driving.
It helps, marginally, not past acceleration. It takes its toll in cornering and braking.
In slick conditions I've found the more wheels I have power to the more the car wants to move sideways. WHen power is on the front the front of the car wants to slide to the side of the ditch, awd, 4wd, or fwd. Rwd same. Awd I always find the entire car just wanting to keep going in one direction. Around a corner up hill, slide straight to the side. Living in the great state of disappointment where straight flat roads don't exist this is an extremely important consideration as the cliff to the side of the road doesn't stop until hell.
Down hill I have the same issues with AWD and 4WD vehciles, less because of the driven wheels, but because of the weight compared to a more traditional FWD layout. Conservation of momentum is a real wicked mistress.
100% RWD is the hardest to deal with, however its also the easiest to predict and correct for in my opinion and thus what I'd rather deal with.