TireRack shows a silver 18x8 OZ SL in ET48 @ $285 each, and 2 different gold versions - an ET48 version @ $295 each and another ET51 version @ $350 each. If you click on "view wheel closeup" in the TireRack Upgrade Garage, you will be taken to a webpage showing the offset, weight, and detailed info on the manufacturing method - cast, forged, etc. The much more expensive - and heavy - 3-piece forged OZ SLIII is also an ET48 design - but @ $740 each I assume it is out of the running.
The gold ET51 version would be a great choice for wagon owners who do have some potential issues with rubbing when using an 18x8 ET48 wheel and 225/40x18 rubber - depending upon suspension choices, rear alignment and tire choice.
But since WReXPower has an '04 sedan he can choose to go with either the ET51 or ET48 versions and have no rubbing issues using any 225/40x18 tire that I'm aware of - unless you've somehow managed to lower the car in the rear by more than 2". the ET51 version may let you run wider tires than 225/40x18 without rubbing. I did a search and found several posts with people running 18x8 OZ SL's with 225/40x18 tires on sedans - as well as one who ran the ET51 version with 245/35x18 tires on a sedan without rubbing. unfortunately, the pictures are no longer visible -the posts are pretty old.