[trularin]

Clois, are you trying to stay in the 11" arena?

12 or 13s will allow more surface area and a greater coefficient of friction. They will, however restrick your rim and tire size.

I do not think you can put 15" wheel on a 13" brake system.

BTW, drilling is primarily used to vent gasses emitted by the pads, it is not a coefficient improver. It will improve the pads performance.

If you are going to increase tires/wheels, the 13" with draft venting to keep them cool. drilled and vented will improve the stopping ability of the brakes.

If the car is too light, the car will just skid. Tires and contact area rule when the brake system is no longer a factor.

Hope this helps.