I can tell you that the fast idle circuit does not connect. Also, you'll have a lot more toe-in throttle response which can get very annoying on a daily driver. Trying to slowly accellerate and decelerate in traffic is not fun. The throttle has more tendency to stick and a slight movement jerks the Z forward and jerks back when backing off the throttle. At higher speeds you don't have that problem. I have one on my 280zx and I'm taking it off and putting the stock throttle body on! I've actually had it on for a couple years and I have gotten used to driving with it, but I remember how much easier it was with a smaller throttle body. And cold-starts suck. I would recommend keeping the stock size throttle body and instead opening up your air flow meter.

Do the "280ZX Turbo AFM housing" with non-turbo AFM electronics. Tune it to work with your engine. Even then, the inside diameter of the turbo AFM is hardly as big as the stock size of your non-turbo throttle body. :-) so they match up good and should give you some more power while maintaining a good even throttle response.