Your car originally had 225/40/18 front and 255/35/18 rear. The idea is that you keep the rolling diameter similar when you change the wheel size. The 225/35/19's that you have on at the moment will show 69.7 mph on your speedo when travelling at 70 mph which is 0.4% out. That's acceptable.
Use this site to find the best size for your new rears:
http://www.ukzero.co.uk/calculator1.htm
The 225M came with 255/30/19's on originally as far as I know and that seems a good size for your car but I think that would rule out Falken 452's as they don't appear to do them. Kumho KU31's would be a decent, if not better, alternative to the Falkens. I'm not sure I would go wider than 255's on your wheels.