When downloadable content for Paradise begins to drop -- both in free and micro-transaction form -- Criterion thought it incredibly important that players not be limited to playing online with people who matched their exact purchasing decisions. The result is a somewhat innovative arrangement where even without buying certain content (like additional cars), you'll still be able to encounter players who might have that content.
Of course, the ability to see content you haven't purchased or downloaded means that content needs to be temporarily moved to your console, which is where the hard drive requirement comes in. We have to admit that it sounds like a pretty good system to us, but we're not the ones without hard disk drives, so ...
