not a simple question to answer quickly.
is there gonna be a ride quality issue? depends what you consider a "difference". expect more feedback, noise, and rougher all around ride because what you gain in metal width, your gonna have to loose in rubber width. and rubber as i am sure you are aware, is a great diffuser for noise/bumps/etc.
the difference in alloy's can be great. rims come in all different styles. some are 2 piece, some are 1 piece. some are made under horrible standards from fly by night companies that get horrible products form china that will NOT pass safety standards here in america. some come already with hair-line cracks.
(reminds me of Forged Specialties - a fly by night company selling china rims marked as "made in germany".
http://www.myg37.com/forums/vendor-comm ... eware.html)
your 100% right: strong light, check: pick any two. you get what you pay for. and for a daily driver, id suggest sticking with good quality rims because you will end up up poops creak without a paddle if you discover cracked rims from a small bump = and they dont make that design anymore. now you have 3 good rims and 1 bad one, without a replacement. common problem.