500k is what you want in the center diff not 50k. I run 50k in the front and the 500k (Kyosho or Traxxas)in the center and 10k in the rear. Any less than 300K in the center will cause too much front transfer. The stock Platinum comes with 100k so going to 120k won't help much. 300k would work well for a loose loamy track but on high bite 500K is the way to go.