Oh, come on.
You're excited and proud of being accepted to medical school (an understandable feeling, btw) and as a result want to brand yourself with this new, silly, status of M0. Your reason for doing this is no mystery to anyone. Do you take us for fools? Your attempt to justify using this term that most people haven't heard used before for the sake of clarity is laughable.
If indeed you don't have prejudice towards DOs, as you claim, but you lashed out with a disparaging comment towards DOs because you felt like it would be hurtful, you have impulse control issues. Do you also lash out at people with epithets when they say something you don't like? You better get this under control before medical school. You are going to realize that you need people's help to learn medicine. That won't be easy with your attitude.
As for your original question, the answer to this is very personal. Research will be helpful and for some specialties you will probably want to have some research during med school at some point. That said, people can and do match every specialty wiut the opportunity you had. It really depends on how much a summer is worth to you in relation to doing the research. Nobody but you knows what you want to do with that time otherwise. Maybe you have a family member who is getting married and you really want to be there, or whatever. Nobody but you fully understands your priorities. The only two facts we can give about this situation are the following:
1. Research this summer would be helpful for your career aspirations.
2. Not doing research this summer will not put you out of the running for any specialties.