Porting from DiRT 2 and/or GRID

It has struck me that we have no decent car models in Garry’s Mod.

Is the GRID/DiRT 2 engine (the EGO engine, same engine used in the recent Operation Flashpoint) impossible to port from or is it just that no one has ever tried?

I don’t really expect this request to go anywhere as Facepunch generally seems uninterested in cars, but I guess there’s no harm in trying.