You could try testing out the mic with someone or a group of people on xfire or another voice chat application first to see if you will have any problems.
Your application should be processed within a day of you putting it in. You should hear from one of us soon about it. (maybe even me, since that is my job
) Since your recruitment would start very shortly after you apply, so there really is no reason to send it this far in advance. But everything should be waiting for you when you return, so good luck!
Also, BFM does not have a PR "rank" in the clan. Being a Potential Recruit just means that you are interested in joining and that current BFM members will be watching you to see if you are a good fit for BFM. The main thing to remember is that a PR is still a guest in our servers, not an admin.
So good luck, and happy racing!