the bigger the wheel, the sh*tter the ride. i have 20" wheels on my R33, and while there is no rubbing etc and the wheels sit under the guards, ie slammmed hard, the ride is hardly comfortable...
i put my stock 16s back on and it rides so good now! 18s with dish are the ideal wheel for a R33 i reckon.
As for tyre size, the 235 tyre may be too wide with a 19" rim. I know that if i fit 235 tyres to my 20s, i need to shave a suspension arm slightly to make them fit. the 225s i have on there at the moment are fine though.
here is some pics of mine with big wheels, looks hot but comfort is certainly lost....
http://www.skylinesaustralia.com/forums/in...howtopic=129884