As for the appropriate CV format, you should consider purchasing "First Aid for the Match" which has several suggestions, as well as other handy tidbits.
However, consider that your CV will most likely simply be typed into the ERAS form and put into their format and downloaded in that form. Its always nice to have a hard copy (which you can download yourself) on some nice heavy bond paper, for your own files and should you need it for scholarships, etc.
I agree with Great Pumpkin - unless your scores and gpa, etc. are pretty poor, getting into a university IM program is not difficult. However if you are considering a competitive fellowship, you do want to get into a more prestigious IM program and I would encourage the research if you can do it. As Tussy notes, some projects don't take much work or can be done over multiple vacation breaks. It doesn't have to break your back unless you're looking for some high powered residency and need to publish to get it.
Concentrating on your USMLE scores and your clinical clerkships will get you further.
Best of luck...