I think you should contact
jim@tirerack.com. He's this site's main man at
Tire Rack (TR).
TR sells the MODA MD1, for the CS, but I only saw 8.5 and 10X18s at the TR site. They are on close-out now, so are really cheap. They are also very heavy; probably as much as 8-10# per wheel heavier than you could get for a little more money.
The offsets of the 8s and 9s you're considering are 10 mm less in the front, and 9 mm more in the rear than the OEM offsets. That means your fronts will move 10 mm out toward the fender lip, while the rears will move 9 mm in away from the fender lip. The fronts should be fine, but you'd need some fairly thick spacers for the rears just to get them back to looking even with the fronts.
Talk to Jim at TR. They also sell much lighter wheels that will work (e.g., Enkei NT03M and OZ Alleggerita) without having to spend Champion, Fikse, or BBS level money. I don't think track wheels are a good item to scrimp on anyway.