This reminds me of the huge shift in focus the Need for Speed series got when Underground came out. The first few games (up to Hot Pursuit 2) were about street racing, yes, but they were about street racing on open highways in the middle of nowhere, occasionally going through a small town. Then The Fast and the Furious came out, and so did Need for Speed Underground, which was based around urban street racing and cosmetically customizing your car[footnote]Yes, I know there was always some level of cosmetic customization, but it was a minor background thing until Underground. Game altering customization (spoiler angle and such) is a different story, and was a standard part of pretty much every non-kart based racer on the market at the time.[/footnote]. I still don't understand why they didn't just turn that into a whole new franchise; it was a huge shift.
Anyway, I have a feeling this will be more like the cosmetic items from Virtua Fighter 4's Kumite mode, with the added bonus of being able to use them online, instead of just in local multiplayer, but that's what pops into my head any time I hear about racing games and customization.