I forgot to mention. The W201 comes stock in my car with the 10P15C. I know some porsches use that and also the 10P15E. What is the difference? Is the 10P15E better? Also, what about using the Kuehl Porsche compressor that replaces the 10P15C? http://www.griffiths.com/porsche/ac/porsac911.htm