As a very recent owner of a new Impreza GT, I query the interval before 1st service. I understand that UK cars come with thinner oil requiring 1st service after 1000 miles. I live in Sweden, and the dealer over here reckons 1st service is due after 12500 km.
I would have thought all new cars would have the same initial engine oil regardless of where they were being sold.

My car came from Holland, but I live in the UK. The Dutch cars only need the first service at 12500km, but the UK warranty requires an oil change at 1000 miles.

It probably is the same oil put in at the factory. Whether it is thin running-in oil, only Subaru Japan can say for sure.

Kevin
MY00 555 blue.