EBay. There are chrome and black versions of housings very similar to OEM except the have projectors instead of refracting lenses. No LEDs.

here is one. I am pretty sure you can find those exact ones or chrome versions for cheaper.
Anzo is not the best brand out there, but not the worst, either.
https://www.ebay.com/itm/Anzo-121144-Headlight-Assembly-Projector-w-Halo-Clear-Lens-Pair-Black/113233503358?fits=Model%3AGS300&epid=83194890&hash=item1a5d3e247e:g:4W8AAOSwSj9bju5O

Edit: Cheaper set: https://www.ebay.com/itm/CCFL-Halo-For-1998-2005-Lexus-GS300-GS400-GS430-4DR-Projector-Black-Headlights/400238480547?fits=Model%3AGS300&hash=item5d30128ca3:g:NXgAAOSwEEBaAfkl
https://www.ebay.com/itm/CCFL-Halo-For-1998-2005-Lexus-GS300-GS400-Projector-Chrome-Headlights-Pair/192618928310?fits=Model%3AGS300&hash=item2cd8fb98b6:g:EI0AAOSw0URbZ5pi

 

 

Please post pics and opinion. I am curious about the light output, for sure. Are you going to sport Halogen or upgrade to HID or LED?

 

Those ebay lights will have garbage light output. Other members have warned of that in the past

 

Worse than OEM Halogen, bulb for bulb?

Are there any aftermarket projector housings that have decent output?

 

Had them on my old GS300. I wouldn't say worse than Halogen but not good as a standard HID headlight.

If you get them, swap out the projectors with real HID projectors. Grab some name brand ballasts, D2S bulbs and problem solved!