Davet,
Great questions... in regards to each of them.... I will do my best at answering.
1) We can absolutely adjust weigh especially if it is putty so much easier than trying to get weight out of a body or trying to remove lead or even worse tungsten... however you would be very surprised to learn that weight even though it does matter pushing it to the exact limit does not really gain you any real speed, if you get your cars to 143grams you will be in excellent shape. We do have expert help to ensure you make weight
2) John's shipping boxes are absolutely the way to go... it is what most of the league racers use, and they will protect your car, and if you follow the instructions you can find on here and it is with out doubt the safest and best practice in shipping cars. I suppose you could put it in a plastic bag, although I would not recommend it... as it could create an issue rather than any risk of contamination.
3) The shipping and return shipping depends on several factors, where you are - the total weight of what you invariably send and the type of shipping (overnight, priority, ups, usps) - Shipping is not going to be too much probably a round trip somewhere near $20 - and I can assure you that you get back well more than $20 of cool prizes and great pwd stuff.
4) Yes we broadcast the races live... and this year with a serious overhaul to the past systems that we were using... it will be very similar to watch a league race.
5) He would run in the Open Scout Division
6) You can find all the rules on the website.
www.midamericaderby.com - we have a lot of great people helping tech in cars and we are checking to make sure wheels have marking intact inside and out, weight, car dimensions, and adhering to all the rules listed.
I hope that answer several of your questions, it is an epic event - and a great way to get started in proxy racing, you would be essentially racing the fastest cub scouts in the United States.