1. I think it would be hard for research to hurt you... but I'll confess that I don't know how much it helped me or would help you. I did it because I wanted to know if I would be interested in research as a physician and because I had a genuine interest in seeing cardiology from a different perspective. It has been instructive and I'm glad I did it because I now know for sure that bench research is not for me. I would not advise doing research for the sole purpose of strengthening your app, but I do think that seeing the "other" side of medicine has been a valuable experience.
2. 8 months seems like an awfully long lag time to me. I thought that the major benefit from my prep class was that I became really conditioned to take the test due to the full-length practice exam schedule, and I think you'd lose that by taking it so early. If you can arrange to take the class closer to the test; I'd suggest it. I took a big financial hit and took a leave of absence from the beginning of February to the April MCAT, and I think it was worth it for me.
Best of luck

to you in this maddening process and feel free to contact me if you have any other questions!