They're nice mate.
Wheel Mania do a similar wheel that does have the correct offset. I know as I nearly bought em, but went for 18" Kahn RS-C instead.
Here is a pic of the Wheel Mania rims:
They are called WheelMania Vortex and are available as either 17" or 18" for the Lexus IS200.
Nice, ain't they? I'm starting to think I made the wrong choice!! Ah well, never mind... The Kahns do look great! And I don't think my wife would be too impressed if I wanted to change them already.