Assuming you're taking a research year and not a personal year...
I'm towards the end of my research year. I'm applying to ortho, so the research is more emphasized than say emergency medicine or general surgery.
Fortunately, I have been productive during this year with more than enough research now. However, I wouldn't say the number of papers I published was my biggest achievement this year. The relationships I made with the faculty at the program I worked at will be invaluable, and I have had multiple faculty members tell me that they want to save me a spot at this program. Of course, I take these compliments with a grain of salt, but when other medical students remark to you about how much the faculty like you, it seems pretty genuine.
The moral of the story is that the research year is objectively to increase your stats, but more importantly, it can be like a year-long "rotation." If you work hard and go way above and beyond the expectations that have been set for you, everyone will notice (especially somewhere that research is emphasized). I have a sibling who did a research year and did the same thing. He matched at that program.