everybody says 19's are bad. I have 19's on mine, and I'd say it has seriously accelerated the wear on my Shocks (OSR replaced twice in a year), and either bushes or drop links (drop links due to arrive soon..bushes a bit later. My car feels knackered but I don't know whether it's bushes or drop links yet).
However, when those parts weren't knackered, it felt fine and seemed to handle okay in day to day driving, but then I guess that's not what you lot are referring to when you say it affects handling?
IMO though, I think 19's were a mistake. The JUN 200MPH car looks superb on 17's, and some of the sexiest Supras I have ever seen (on t'internet) rode on 18's. I think if the ride height is right, then 19's don't look any better.