I've done this on my 1993 model. It requires a bit of work but it's not an insurmountable task. Fog lamps are much more useful than the early cornering lamps, even if you have an HID conversion.
-1997-2000 front bumper conversion (and the little bezel in the grille & Lexus badge, etc.)
-97+ fog lamps (of course)
-x2 Nuts (rear of housing) 90179-05088
-x4 Screws (top and side of housing) 90159-50225
-97 fog lamp connectors (can't remember the P/N but it is in a thread here)
-Spare electrode/wire for those connectors if you have anything you've kept from phone wiring, etc. If not, Sewell Lexus or Carson Toyota can probably source them for you
-A custom made foglight wiring and relay harness as per O.L.T.'s thread listed below (I also recommend some round plastic wire protector tubing while you're at Radio Shack)
-An interior switch
I won't go into great detail but other than the bumper conversion you have to clip and tie up your cornering light wiring that goes in the same location as your future 97 fog lights. It's unusable because the voltage is around 15v and variable depending on whether or not the headlights are on and whether or not your left or right turn signal is on. So you must create your own fog wiring harness. It is best to wire the relay trigger (as in the thread) to your parking lights rather than your headlights. This way your fog lights can be switched on independently of your main headlights but will also shut off along with ALL your front lights when you turn the factory stalk to "OFF" or leave it in "AUTO" and the car senses that it's daytime.
Here is the meat of creating the harness, thanks to O.L.T.:
You can also search for other visual diagrams online (i.e.: "how to make a foglight relay harness") and you will find it's the same basic principle. I'm very visual and needed more picture examples before doing mine but his guide is exactly how you do it and helps you identify some crucial SC specific wiring.
Then there are a few threads I made to clarify some things:
And finally a DIY I made detailing how to cleanly get your aftermarket on/off switch into your dash area. You COULD try converting to a 1995+ light control stalk with the foglight selector but this is even more involved and involves getting into the steering column collar. So the easier solution is adding a simple interior switch.
Good luck and hope this helps!