i would like to use it as a real estate mod so players can buy a land (grid) and not be bothered connecting to a neighbour in front of their base 
is it possible to do just that? pay for a grid and it block others from building but they could still harvest and farm maybe with a tax i dont bother ^^

Not possible right now to completely block players from building inside the grid.

But there is already a rule where any faction member can raid any bases that don't belong to their faction in their claimed grids.

So it is not exactly what you need but atleast faction owners can evict unwanted neighbors without having to declare wars.

so if i understand it correctly could i run your plugin just for what you explained? 
if someone build on my claimed land i can raid him ? that's it nothing more
is it possible? disabling other aspects?

Merged post

it could be pvp only against foreigners if they enter my land 
but will it work with truePVE mod?

It is not possible to allow you to damage other players while they can't fight back.

The closest you can do is set your faction to badlands using /faction badlands so your entire territory allows pvp between everyone.