I think it has something to do with the history of each series. I mean NASCAR has never really had wild schemes while the V8's almost have always been out there. That's my take on it at least.
Pepsi Max for as long I can remember here has always used the graffiti thing pretty hard in its marketing. They have added some green to the bottles with a cash or car promotion they have going at the moment.
It has to do with the marketing differences between thr two countries.
I would say that's pretty accurate. It may also have something to do in that respect that even though it's Pepsi Max, Pepsi's gonna sell itself so it's mostly backed by commercials and such.