[DRLOWZ]

Marco, have you tried places like this:

http://www.usedpartx.com/

This place seems to have aftermarket OEM lights:
http://www.headlightswholesale.com/1...il-lights.html

Here is a shit load of Buick parts:
http://www.salvageautoparts.com/buic...buy_parts.html

Just for kicks here is the history of the Riviera:
http://www.musclecarclub.com/musclec...-history.shtml

Hope some of these help ya.....