I have been involved for just a little under a year. I have recently stopped because I am saving my money since its friggin 25$ an event.
Yes its a great, its fun and you can test out mods really well.
I am pretty sure that there are more probes than mx6's on the boards that autox.
www.probetalk.com/forums
not sure if youve been there, but there is a more complete 'racing' forum there if your interested in learning about things to do for your mx6.
just ask questions or use the search.