I have a 2011 R-27 and replaced the stereo a couple years ago. I have newer chart plotter installed also, 8612xsv. If you still have old chart plotter, some info that follows will not apply, but mount and hole size are the same. My old stereo was a MS-CD600, which is same mount hole size as MS-IP700i. I installed a MS-RA670, works great and can control from chart plotter, which I love. The MS-770 would also work, it costs $250 more, has built in wi-fi and Apple Airplay. The MS-RA670 part number is 010-02138-00. You will also need a retrofit faceplate kit, part number 010-12829-03. Looks fine installed, basically it extends faceplate to either side, looks like part of original unit. Again I have 8612 chart plotter installed. Because this 670 stereo is not wi-fi, I connected to chart plotter via LAN cable. I also connected SiriusXM antenna, mounted where original TV antenna was removed. These cables were run behind cushions above V-berth back to stereo head unit.