[CaraHime]

By Shibuya girls you, of course, mean Gyaru, right? I agree that a lot of stuff is a little on the preppy side. It's only natural that they would share some elements since Gyaru came from Japanese girls copying California girls. A good example of this would be Uggs. (-shudders-)
However, some looks, such as Haady Gyaru, are totally different. Haady Gyaru looks more like a Gyaru manifestation of Scene, in my opinion. Manba, Banba, and Himegyaru are a few styles that you could never tie preppy fashion to.

I would post pictures, but I don't feel like it at the moment.