1. it is, but it is included in the entry fee. you pick up your transponder when you sign in at registration
2. if you have a race tail, it should be ok. 6 inch numbers are ok to use, I have seen people putting it on with no problems.
3. competing? nothing like it. even if you are racing for the 30th place like how must of us started out, you will be just as excited and involved. Just keep a level head, and pay more attention to where you are going, not to the guy you are racing against. If you are faster, you will beat him, if you are not, then don't go over your head trying to keep up. Thats for later on in the year :p