Check with your local PCA for a good reference on a trusted A/C shop in your area. They know who the good guys are and who the snakes are. Here is a generic list:
Porsche Repair Shops & Mechanics in Utah | PCarShops.com
I damaged one of my radiators about 4 years ago and the process of replacing it put stress on the condenser o-rings. The refrigerant leaked out but a recharge was all that was needed. Still blows cold.
Other possibilities are a failed mix flap preventing air flow over the evaporator. Foam coming out the vents is the symptom of this.