63 Dart defroster vents

Has anyone had any experience with these defroster vents:
http://www.ebay.com/itm/170896479115?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Does anyone have a suggestion for a good product?

I am painting the car B5 so they will need to be repainted, is this a problem?

Thanks folks!
John