Fitted my D1 throttle controller today and very noticable the difference in feel and, frankly, enjoyment. (suspected future potential increase in petrol consumption aside - which frankly is not why I own a z)
I was going to go for the re-map, and may well do so still - but at £25+ per HP gain (with Berks /Y-pipe etc) at present I cannot justify it...
The 'problem' with the Z IMHO (having owned 500HP R33 and Soops before) has always been in the crappy first to second gear ratio... this feels much improved and as a result I am much happier with the car now!