Funny in Japan there's a huge choice from 2 or 3 piece wheels!
Not 18 inch though, 16 inch.
I personally prefer the one piece, cause of its clean looks.
I've seen the 18inch wheels live now and without wider tires, they just don't do it for me, too skinny, like a insect...
I'd prefer to go for 16 inchers then and put a thicker tire around them..kinda like Davers VX. The same is possible with 18's but at a higher price and less choice..