With 19" I feel no perceiveable difference in ride over the 18"'s I had previously.... I think you will find "genuine " rims will corrode just as well as aftermarket makes if not cleaned/ waxed regularly..a lot of people have had issues with Rays bubbling on paintwork due to corrosion
What do people wax their wheels with?
For me - Megs liquid wax. It makes them so much easier to clean. Just remember the insides!