There's nothing magical about a National, so why pay the extra $$$? [/b]
One good reason, with the pending demise of the closest track to me and the next nearest being a 200 mile each way tow, I could do one double national weekend and have enough race credits to renew my national liscense instead of having to tow 400 miles 2,3,or 4 times to get enough regional races to renew. Ends up being cheaper in the long run.