Questions on Sauromatae gameplay

[Liberator]

speaking of exploits, ive noticed that the enemy gov building works sometimes and i can build my highest lvl happiness structures in italy using Seleucid. is there any downside to doing this??

you may receive a small culture penalty, as the government building is foreign by its nature.
but thats neglectable; if the province is far from your home provinces, this may be the only way to build all buildings (and get all benefits they offer) of your faction.
As all government buildings, a enemy gov building has an impact on the recruitment buildings you can constuct.