I own 3 280zx's. 1 x 1980 (reciprocating ball) and 2 x 1982 (power rack and pinion). One of the later cars is off the road for a full rebuild but I have recently driven both the other cars hence can do a back to back comparison. I'm not a professional driver by any means and both of the running cars have not been freshened in the suspension for a few years. I bought all 3 cars around September last year and both running cars were tram-lining over undulations in the road surface and would wander on a straight section of road as well as being twitchy and unpredictable in the corners. Definately not like you'd expect from these cars. All I did to fix the problem was to correctly adjust the front wheel bearing pre-load and now they both drive and handle beautifully. I didn't adjust either car very much to get a big change in attitude through the steering. I checked that the rest of the steering was in good order as well. I don't notice too much difference between the two types of steering for the type of driving that I do which is as a daily driver on the road but I would say, that the rack and pinion seems to give a more confident feel through the steering wheel. This of course could be as much to do with the suspension in each car which is not identical as it has different brands of shocks but still have factory springs in each. So the test really is inconclusive unless I spend the time to change suspension on each car to get a better comparison. Not likely to happen though.
If you like I can get some dimensions of the moving parts like the diameter of the main shaft and tie rod ends etc so you can compare it to the earlier S30 racks or to other racks. I won't be able to do this until I get home on Tuesday.