My experience is the M grip on the front on carpet is very aggressive. Your friends tires could be a little more worn which will take some bite out of the front. A basic tire setup on carpet here is s grip fronts and type a slicks on the rear. I usually lean towards a little more rear grip than front and balance with tire additive on the front. Sometimes we used just the inner two rows of tread on the fronts and the whole rear. This is just a generic setup. If your not bound to Tamiya tires there are better choices.

Also I use the rear swaybar for fine adjustments.. It's not a fix all dramatic change.