MMSA is a spin off of AMSA.The rules are very much the same except AMSA motors are not sealed and top 3 in every race are tech every race.Weights are about the same this year and you don't pay a extra fee to race with AMSA.After you pay a guest entry for 4 weeks you are automatic a member and points start counting.Payoff is the same member or not. If you can Print off the rules and compare to see both to see what fits your progam.Jerry Tague would be glad to answer any questions you have and has been associated with mini's since the 80's .