See here for his other bikes incl a couple of FZ1s:
http://www11.ocn.ne.jp/~ys4031/custom.top.htmlHe seems to know what he's doing and has done most of the work himself. It's unusual for anybody in Japan to have a FZS600 as they were, as far as I know, never sold there with only the 400 & thou available. The licensing system over there basically means that there is no market for 600cc bikes. Definitely a heart over head thing. He must be a bit eccentric, mind you spending lots of money can't be much of a concern for him judging by the number of bikes he has
As for the TPS, he says something like he "machined it to be thinner". I've never actually taken the TPS off myself to get a good look at it so its difficult to say, but I think he's referring to increasing the inner diameter - ie I reckon its basically what Kebab19 said, he bored it out.
As for the wheels, they are TZ250 Marchesini rims with spacers he made himself. I think the choice of wheel is a cosmetic thing and not of particular significance.
Does this mean that a front end conversion might be possible? Maybe its time to start experimenting with the TPS unit....