A serious wheel question that goes beyond weight and appearance...

[ultra]

It might be possible to run 19s and have the wheel + tire weight come out near OEM weight if you go for expensive forged rims and the right tires, in which case it should still work well with what the OEM dampers are designed for.

Might suffer from a little more harshness in terms of ride quality though.

For a staggered setup it would seem that wider rears would add understeer, but you could always look at running square-ish rubber on staggered rims although I don't know how that would look.

Jury's out until somebody does some actual testing IMO.

[armythug]

Everyone always mentions upsetting the balance of the car. In my opinion, the balance of any car starts with the owner/driver. From there, you set the balance of the car based on your personal needs. Isn't that what tuning and modification is all about? So in my opinion, upsetting the balance of a car would be when someone other than yourself makes a modification to your car. Or making a modification to your car and not experiencing a satisfactory result. So if you want to put 19 inch wheels on your car and you're satisfied with the result, you're not upsetting the balance of your car. You may be upsetting a fanboy by doing that but who cares. It's your car. And you may not be a race car driver.