I would let people race the MO5 in club racing once they are released, as I don't believe you can force them to buy a MO3.
BUT, before anyone goes off half cocked, if though you want to compete at any of the big events, then you will need to run the correct chassis as stipulated in this years MIni Rules. I think that this will be easy to enforce.
As TG stated
"The mini rules will be reviewed before the end of the year and adjusted accordingly for next year."
Happy Racing.
Regards,
Calvin.