I have just written off my series 2 Stagea (NEO, as such i beleive they will do ER34 as well). As such i removed the ECU fitted with the type 4 nistune board.
This cost me 300 for the board, 100 to get it fitted and 130 for the ECU.
Its tuned for a z32 air flow meter (also removed), a GCG hi flow )running only 1 bar), pod and 3 inch exhaust with a walbro fuel pump.
I didnt get around to fitting bigger injectors, hence the low boost.
After $700 for ECU and AFM which includes the plug.
It was mostly road tuned, very safe A/F ratios using a tech edge WBo2 sensor.
ECU is 23710 0v801, for a series 2 rs4s and ER34 (manual obviously)