Ahh, the ol' RB26 PFC misfire.
I believe it is an earthing issue but it can be a pain to run down.
The Nistune is the best bet today for a streetable car.
(I had a slight miss on one car around 2500-3000rpm due to the relative difference in the mapped AFR vs closed loop.....the step was too big to provide a smooth transition, leaning out that section of the map ironed it out totally)