In my opinion there is or there will be a lot of small tweaks like the mini 1300 which is very nice to drive by the way.
Different engine, rwd, maybe a project Binky 4wd! There should be some kind of tree or ordering, maybe force (or encourage) people work together or do some contest to choose best version. If there is ten different 1300 10 different 1400, it will be a mess with a huge dilution... Maybe also some classification like race, oval, drifting, drag, tractor pulling...