Phantasy Star AotI expansion set for XBLM release

Recently, SEGA announced that the new Phantasy Star Universe expansion, Ambition of the Illuminus, will be headed to the Xbox 360, but only via a download off the Xbox Live Marketplace. SEGA is setting the Ambition of the Illuminus expansion for a worldwide November 20th release onto the XBLM and it will be priced at 1600 Microsoft points, which is cheaper than the $39 PS2 / PC retail version. But know that you must own a copy of Phantasy Star Universe for the 360 to play the new downloadable expansion content. But then again, why would a person purchase an expansion pack without having the original game disc. That would just be silly, now wouldn't it?