For some reason a lot of one make series dont last. Swift GTI, Mirage, Minis to name a few.
There is also a new one for N14 and N15 Pulsars starting next year.
As for keeping the motors the same, they use sealing tags so you cant pull it back apart. I had to build mine in front of a guy who measured/ cheeked everything to make sure it was ok. The combustion chamber was a about 3cc out so I had to get that fixed before he would put the tags on it.