As far as I know, the rules about what you carry, ie warning triangles, spare bulbs, reflective jackets etc are country specific. So any car in a country has to have those bits and bobs as laid down in its own legislation.
Rules about construction, ie size and number of registration plates apply as per the country of registration. If you don't have a front numberplate in the home country, you'd not need one the country you are visiting.
Extreme case that I think is legal, you could visit from the USA with a red flashing light at the rear for an indicator and be legal as a visitor (it would not be legal if you registered it here though).
