You can go 6000k. Just get a 55W kit which will make it look 5000k’ish.
If I was doing another retro, here is what I’d do:
TL Projectors
ZKW or ZKW-R Clear Lense
6000k 55W HID Kit from DDMTuning.com
or (if my headlights were of a smaller size)
FX-R Projectors
Same HID kit
I wouldn’t consider anything else.