If you take a cross section of X Japan' fans in Japan you will find a strange mix of people. On one hand X Japan endears itself to metal fans, given it's heavier roots and occasional speed metal epic. On the other it endears itself to younger Visual Kei fans, who are largely enticed by the genre and on another you have the middle-aged women demographic who adore X's ballad music and follow the band in a similar esteem to how middle-aged western women follow rock bands such as Bon Jovi. When I was at the opening night X Japan's reunion shows in 2008 at Tokyo Dome I was sat behind an adult woman with her young daughter, I was sat in front of two teenage girls dressed in Lolita dresses and sat several seats away from two middle aged metal heads. I think that goes some way to explaining the point I'm trying to make.
It's difficult to place X Japan's exact demographic because their diversity has gained them fans from many different sides of the spectrum. I think that their launch into the United States is unlikely to see the band entirely focusing on one style of music, but instead adding to the range which they already cover, as let's face it, a lot of X Japan's back catalogue now sounds significantly dated - even in the late 90's X Japan sounded like band fresh out of the 80's. We already have a rough idea of what their album is going to entail, and as such I think if we were trying to establish a single demographic which said music would endear itself too we would be looking at a minority of eclectic individuals at best.
As tragic as it may be, I don't think X Japan's success or failure will have much to do with the music they put on out on their new album anyway. I think it's going to have a lot more to do with how much mainstream exposure they get, and appearing at Lollapalooza, in my mind, simply isn't going to be anywhere near enough.
However, my inkling is that there is going to be a product tie-in with Myspace closer to the album launch. Yoshiki has been playing sweet with Myspace's chief operations manager (he was a VIP at the Hollywood filming event in January). So I guess we'll see if and how that transpires.