For cars already properly tuned on pump fuel with the PMS
using a centrifugal supercharger:

Make a base run and watch the Air Charge Temp in the PMS and write down what it is at max boost. After installing Mr. Freeze, make another base run and again watch the ACT in the PMS at max boost. You should see a drop of 60 degrees or more. Given these results, on average you should be able to go into your PMS and lean down WOT fuel tables by 6% to 10% and add about 9 to 15 degrees timing at WOT or in the boost tables.