GI will want a real researcher as much as any field of medicine, but since it is so competitive now, you better be able to sell yourself as one. Not having a PhD will make it tougher, but if you have a strong research background, you might have a chance. The more basic, the better. The fact is, any applicant to any competitive field these days has to have some research to be competitive- whether it be cardiology, GI, derm or rad onc. The challenge to programs is differentiating the ones who have research to pad their resumes and the ones who are really interested in making their careers as academics. Just about any GI applicant these days has some clinical research, so I'd if that's what you have, it better be really hard core stuff, if not NEJM then close.
And forget about research during residency, there is simply no time to do substantive research in your intern year. And clinically, they want to know you are competent, but that really isn't what its all about either. I get the impression that programs don't really that much care how you did in med school either. As long as you are coming from a reputable medicine program, research is the single most important thing that will make or break you. I'm short tracking into GI, and didn't have a big problem with it. Then again, I have a PhD. I really think it would;ve been way tougher as a straight MD.