I think the original tires for the 13 RDX tech was the Michelin Primacy MXM4 grand touring all season (P235/60/18 102v). I've had OEM Michelin's on my 06 TSX, 08 RDX, and 11 MDX and they were not that good in colder temps or in light snow covered roads. The Michelin's also got louder as the tread worn down. I switched to Continental DWS tires on all three vehicles and was very happy with grip, 50,000 miles of tread-wear, reduced noise levels, and improved all weather capabilities.
Unfortunately, I don't think Continental makes the DWS 06 or DWS 06 Plus in the 235/60/18 size?