I need to change out my a/c compressor on my 95 blazer I have a shop that will flush the system and recharge as soon as I am done. Am I better going there first remove the freon and oil and then change the compressor or should I just change the compressor with the freon in it and then take it to them and have them flush it and fill it. I would like to change it and then take it into the shop. Am I dangering anything or do I have to worry about condensation, Any help would be great. What would you suggest.