Everything I've seen and heard implies that board scores (esp Step 1) are far more important when it comes to matching - especially on the allopathic end of things. The 3/4th years interested in matching an allo residency at my school all tell me that the first question that comes up in any discussion on matching is "what was your Step 1 score?" It seems most allo residency directors value grades far less than board scores, and the NBME surveys on the subject have consistently backed this perception up. After all, many allo med schools are P/F, and many schools that aren't P/F don't rank. I gather that the osteopathic side seems to take grades more seriously for whatever reason, but whatever.
That said, I'm not saying that the grades absolutely "aren't important" - I'm always gunning for honors without a doubt, and every additional thing you can do to distinguish yourself helps. But when you go to a school where the curriculum isn't particularly boards focused, you can honestly ace the classes and still set yourself up for a mediocre performance on the boards if you don't fill in the gaps (and it's happened a fair few times around here, as far as I can tell). I guess my point was more that people absolutely shouldn't get too overconfident about the boards just because they've done well in their classes. Strong class performance doesn't always translate into strong boards performance, and it's clear that the latter matters much more than the former.