if its 2 ohm stable... that just means it can handle a 2ohm load... Ive never seen a car amp rated at 2 ohms... they are always rated at 4 ohms... and if the amp is capable of driving 2 ohms, they will give the 2 ohm output as well.

Who knows though, being its from another country. But if the amp will handle a 2 ohm load, a 4 ohm load will be fine.