No response from anyone but I think it only takes two. I'm now thinking about the pro option as I would be able to do my own PPI's on any future cars I would consider buying. The first one I do covers the extra cost. Can you imagine the look on dealers face when you pulled the fault codes and DME right on the lot while negotiating? FYI, you can text me at 405-550-0207 or email me at bclark@rfip.com.