it's nice but it ain't worth. Buying the car outside US and ship it here will all the tax, emission, transportation and etc fees. Overall you will end up the higher that the price if you buy it here from the US. If you wanted an impreza sti with 2.5 300 hp. Why not just get the engine and ECU itself? If you wanted an Evo8 with 270-280 HP why not just tweak the engine and get the parts that will allow you to get that number. I heard EVO are just the same only they have to tweak it a little for US street legal standard.
I think you go the wrong idea buddy, he wants to buy a supra in the us and then ship it over to belgium. Not the other way around, plus the STI and the Evo were just for comparison he didn't actually want to buy those.
Now to the original poster, In the US supras are also pretty hard to find and they do cost a lot, alos with modifications that you will have to do to make it street legal in belgium(if there are any), plus the tarrif on export/import, you will end up paying so much more.
So I would recomend settling for something else that is available localy.