I had access to an evac unit from a local shop. Since this is the last phase of the project (as mine was leaking so badly it would bleed out any charge in a matter of hours) you could complete all assembly and take to a local shop for the final evac and recharge. I think you are wise to put a new expansion valve and drier, I did the same. Let me know if there are any questions you might have, I do not know how different the S500 is under the dash but do not be alarmed by the cobweb of wires you will see. It was obvious to me where all of the wires went except I labeled 2 wires that detach from the airbox because they were ambiguous in nature.