Speaking from experience, I suggest that you don't bother with them unless they're actually serving a functional purpose (like if you have vision problems) and you go balls-out on a quality kit.
if you truly want a direct drop in/ plug n play check out the TRS(theretrofitsource) H11 extreme kit. it costs 150 but allows your stock projectors to look very decent, not 100% as crisp as a TRUE retrofit or STOCK HID's but still sharp nonetheless. here's a vid of my car with that kit and 5000k temp. http://www.youtube.com/watch?v=B19G2RvoKuY