Volvo Repair: S60 A/C Control Unit, complex computer systems, money back guarantee

Question
I found out that my control unit is going out(a Volvo dealer pulled the codes)the fix through them is $1000+. I found a used unit with money back guarantee and a repair shop that will do the install but it will cost them about $300 for the software downloads. They wanted to make sure that the unit will take the downloads and the guy selling doesn't know. I want to know if I buy this unit is it possible that the shop can't download some software into it and it might not work. Right now my unit is blowing semi cold air so I don't want to go to nothing if it doesn't work.
Thank you for your time.
J

Answer
Jon, 300 bucks for the downloads is outrageous.  you are getting ripped off.  These are complex computer systems.  I wouldnt take the chance.  I take it the car is out of warranty?  how many miles? Personally, I wouldnt take a chance on any used unit.  WIth Volvos parts warranty you have a 12 month limited milage warranty.  Roger