Thought I would update the thread just so you know I took advice
I mentioned earlier than I had Z1 intake tubes , I actually had some Mishimoto ones which arent as good quality as the Z1 ones and since my tuner reckoned the MAF readings were a little screwy I ordered some HPS ones (incidentally there is very little difference between the two) to be sure.
Also bought some Berks test/decat pipes and fitted those
So before was 309.4 flywheel HP
After just fitting the above parts it produced 328 flywheel HP but it had leaned out .....a lot !
After an Uprev remap and smoothing it made 345.9hp. +36.5hp increase
The car drives a lot better especially at the top end and ultimately that's what's really important , I will however get a run done on a dynojet dyno to compare at some point
So thanks all