Mark you want to get fully mappable ignition system, no lie this is the b@ll@ks

its not that expensive either around the 300 mark, basically you decided what the ignition system is doing, ie you can retard it once the nitrous is running etc etc, been told its well worth the money, you plug a laptop into a go from there.
Facet do some top fuel pumps which can be adjustable to alter the pressure to suit your car. You may have the problem of getting more fuel in there, depending on injectors and the ecu...
So whats the difference with the j spec to get an extra 30 bhp? over the uk car?