Like James (Sklyn) I recently installed / Tuned an SAFC2 and found the Response, Midrange and Drivability improved greatly.
Totally Different car. Not sure what the before figure was but after the first tune I got 181.8rwkw. Much Better pickup.
That tune was backed off due to potential Timing belt issues.
I got the Timing Belt replaced and a retune saw a further increase to 192.4rwkw but this tune is also not to full potential.
My engine seems to want to start pinging when normally it wouldn't. My "Tuner" reckons it's acting as though the compression is higher than it should be. Maybe the head has been skimmed more than normal.
(Series 2 R33 RB25det, Pod, Metal intake, RB20 10psi Actuator on Stock Turbo, ARC smic, 3" Exhaust, Bosch 044 intank.)
But only being an SAFC, I would've thought a Nistune would open up alot more than 10kw.
I'd seek a 2nd opinion / tuner. Compared to an SAFC, something doesn't sound right...