bob!
nice Nismo kit you have there!
APS kit is imo at the moment the best TT conversion for the Z, BUT it's getting a bit too common in the UK (basically everyone who has a TT has an APS kit). This is also due to the fact that there is NO alternative in the UK at the moment. Tuners are simply playing it safe and are not interested atm to "invest" in other valid kits out there.
Also, since there is no alternative, prices are kept artificially high ( i know of a person who had his kit bought and fitted for £5k , surely the company who did it STILL hasn't lost any money? ) If you go down the normal route, you are looking at over £8,5k which is ludicrous, when in the US these prices are basically in dollars...
In UK we need some proper competition, to make prices get to an acceptable level...