It is relatively common in the UK to get 'parrallel' imports (thats bikes that are available in the country you are in, you just buy them from overseas, - Grey imports are bikes that are not normally available in the country you are in).
I have just bought a US spec import, the only difference is the clocks and headlight adjustment and the dealer rectifies these before sale.
I think the only country in Europe that has huge differences is France, from recolection, when I had my Blackbird I know that the French version was massively limited on power.
In my opinion, if you are buying an import from a dealer, then go ahead, but I wouldnt ship a second hand one myself, if it goes horribly wrong, you dont have a leg to stand on.
Just as a comparison, I paid about £7,600.00 Sterling for my K3 US import.