found a site claiming to have intakes for the rivs!!!!

http://www.eautoworks.com/html/ORD-1-1-1-106311.cfm


http://www.whipaccessories.com/product/Weapon-R-Secret-Weapon-Air-Intake/Default.aspx


http://www.ilovebodykits.com/product/6555/Weapon_R_Dragon_Intake_92_03_Buick_Riviera_3_8L_V6.html

all i did was go to google products and did a search buick riviera cold air intakes let me know what ya think if any would work?

The Weapon R systems don't fit.
I bought one a while back and had to return it.
It's overpriced and not worth it

Rick is correct. Generally, any product claiming to fit 1992-2003 Rivera - that's a good clue right there they don't know what they're selling. More info here:
https://rivperformance.editboard.com/series-i-engine-transmission-f13/weapon-r-intake-series-i-t4678.htm#62427