Many have swapped to the Kouki's, many want to but cannot afford to, and many feel the general shape of the Zenki is just better and that Koukis are too 'edgy'.
I personally love the sleek/contemporary style of the Koukis, but I also enjoy the smooth blends of the Zenki. The Zenki's fall back though is they are typically more brown/burgendy than they are black (Due to aging) and the general style of the lamps themselves are nice but boring. I want to improve the Zenkis for my car to have the best of both worlds, in a sense.
Here is a photoshop I did of some Zenki's and my proposed idea.

(Thank you to whomever's car this is, probably one of my most favorite S14's)
I would completely remove the reflectors from the center section, leaving ONLY the reverse lamps. If possible I'd love to enlarge the reverse lamps to both look better and provide more lighting whilst backing up, but I dont think that will be easy. I also want to add small seperations between the stop lamps and turn signal lamps as well as round the edges of the lamps and remove the corner reflectors. The entire assembly will be finished in black to represent a new housing, I'm hoping to paint it from the back side for longevity as well as general appeal.
Let me know what you guys think, I know the center sections have been blacked out before and it looked pretty good but I want to improve upon the corners as well.
~Kris