I don't think you can say the UK car I have referenced is inferior unless you have physically seen them both which obviously you haven't.
I have bought and sold 3 superb Lupo GTI's over the last 8 years and remain very close to the market. Despite people banging on about future classics and an appreciating asset the price of a standout UK car has remained sub £7K. There was a company in Bristol a few years ago who imported a fair few Lupo GTI's from Japan and they priced them about £750 to £1000 below a comparable UK GTI, which I think is right.
The Japanese imports are only available in the least scarce colours of black, silver and red. They have increased standard spec of aircon and side airbags but I have never seen one with a sunroof, leather or heated seats which leads me to think these options weren't available for the Japanese market. Service history etc is of course a whole new ball game.
I wish you well and it's nice to think there will be a couple of more GTI's available soonish.