Hey modelman,
I agree with you 500%. Not only are they too small, but they don't even look correct! At least Tamiya did a perfect job of replicating the UK spec wheels on their STi. I've been pondering this issue for a while now.
Anyway, the domestic STi uses 10 spoke BBSes, and these are about as close as you can get:
http://www.spc.org.uk/wheels/fujimi/kranze-shoki.jpg
http://www.spc.org.uk/subaru/cusco-gdb.html
(Hope you don't mind that I linked to your page Hiroboy!)
They're definitely NOT perfect, but will fit on without any mods whatsoever. The problem is that they have an "edge"/dish look, whereas the BBS spokes go right the edge of the rim. Another wheel that comes close are the ones on the Tamiya Porsche GT3, but this one requires modifications. Also, Fujimi released the STi Spec C that shows the correct wheels on the box, but I don't know if they just included the kranze-shoki's or if they're actualy accurate (I've come to expect the worst from them).
Lastly, I was thinking of putting on wheels from XS tuning (either RS Touring or RS Speed
http://www.xstuning.com/speed.html) to replicate Prodrive PFF7s, which my friend has on his scoob. Final option would be to get the Tamiya WRC kits and steal those wheels...
clem..