Most US grads will not have any problem matching into a decent university-based IM program. A lot of programs really don't look at your Step 1 scores as long as you passed. After that, it will depend on how well you do during your first 1-1/2 years of residency before applying to cards fellowship. Cards research and your PD's letter are important.
For non-US grads, I think they look at your USMLE scores more closely since they can't compare your medical education outside the US quite objectively. My guess would be that you want to at least beat the national mean, which I believe is around 215.
