I have 255/40 & 295/35 currently, somehow an odd size but looked great if you ignored the height.

http://www.the370z.com/3484155-post10.html

I think your best bet for more meat will be 255/40 & 285/35, but not sure of front rubbing even though I run +22 wheels in front without issue, or 265/305, but will be a little shorter then mine but meatier than yours.

The reason they seem like they have no profile is there's really no reason to run a 30 series tire with those widths on a 19. OEM nismo rear would be 285/35 on a 10.5 and a 245/40 front.

For aftermarket, I always recommend going wider. SINCE you're not lowered at all, you really don't have anything to worry about. You could easily run a 265/35 front and a 305/30 rear or a 285/35 rear and add a 15mm spacer.