What year model(s) of the S4 would I need to look for, in order to get a direct fit?

 

the b5 00 - 02

 

you can reroute aftermarket fogs to the lower grille and tie them into the fog switch otherwise yes you loose the fogs.

 

Yep to all of the above. The ones I have are listed asB5-generation RS4 lights, and they're two-piece so there is no fender trimming. You do lose the fogs, but I bought facelift fogs and installed them. The green/yellow wire in the headlight harness is the fog wire - simply use a wiretap to connect to it, and do as SAudi said - run the wire down to the facelift fog, connect it, and ground the other fog bulb terminal. The seller on eBay that I bought from was MakotoAutoTrends - look them up in the eBay community link and you can dig through their auctions or contact them about the RS4 projector lights for the B5 A4.