Being one of those mentioned p192c-ex maintainers (although currently in maintainance vacation), I agree with Flemm.
I don't think we need a subforum in the extended section. A link to the standard subforum and tags should be sufficient.
p192c-ex developement is tied very closely to the standard version. Practically the only difference is the economical balancing due to new features as well as some vehicles in standard being delivered as addons, whilst those are contained as liveries in the extended pakset.