I did it and highly recommend it if you're aiming for a hyper-competitive specialty.
That said, make sure the academics are squared away first. Worst case scenario would be that research compromises your grades/step scores. You probably won't be able to do research at a high enough level to overcome academic deficiencies, so academics have to come first. But once you've got a system dialed in, it's worth the effort to get some projects going. They may take quite awhile to finish but this gives you plenty of time.
The other reason to dial in your academics first is you also don't want to make a bad impression on your research mentors. You want to be able to deliver on your projects and if you have to side track them for your academics and end up not finishing things as promised, then you may come off looking bad.
This is why most places generally recommend your wait a bit into M1 before starting anything just so you know what it will take from you. Med school is definitely drinking from the fire hose, but it's hard to know what that means for you personally until you've done it. If gunning full out lands you 98-100% scores on exams, then you can probably dial it back a bit and still do quite well. If you go full out and are barely passing at all, then you probably don't have time for research and may want to rethink the hyper-competitive specialties entirely.
Me personally, I cold called my mentor before my med school interview and we met after interview day and hit it off and got some things cooking before classes even started (IRB, etc). We had talked and had built in a pause to early M1 so I could make sure the workload was doable and this coincided nicely with the data collection phase of the first project. I've always been a bit unconventional though, and I'm not sure the extra time mattered terribly much other than it did let me start going to meetings and networking early.
