Indeed, S15 Silvia... with a few tweaks. Brakes you can see, RB30 you cant, in those pictures
I understand what you're saying about 19s, it's a matter of personal preference I think.
19s look great, and tyre prices for them are coming down nicely now so many cars have them, and they work well on the Zs
18s generally tend to be a bit lighter, save a bit on tyre price and allow you to just swap your tyres from standard wheels to save a load of money. There's also more choice in 18s as they fit more other cars, so can be stocked more.
I'd never had got 19s on my car, those only just go, S15s are rubbish for wheel fitment
Ben