The XAR is a stand alone regulator. I never saw a Link 2000 "R" that came with an XAR and the XAR came after Heart Interface as it was a Xantrex only product. The "R's" all came with the older square metal box connected via a data cable to the distribution board and then onto the Link 2000 display via a large ribbon cable. The programming for the regulator was done by the Link not at the regulator module. I have seen Link 2000's installed on boats using XAR's or Balmar regs (both are made by the same company) but those are not the same as the Link 2000 "R".. Perhaps Xantrex began shipping Link 2K's with XAR's and I missed it but I never saw or knew of a 2000 "R" with an XAR as the reg. I have however managed to salvage a 2K-R display (monitor and I/C control) by disconnecting the "R" portion and installing a Balmar reg. You lose some of the features of the 2K-R but it saves some money when the regulator portion goes berserk...