one thing I did find (this is not a for a Rb26 though) R33 and C34 will pinout correctly for a PFC but the ECU A/C signal will not be sent out if you do the ECU swap using a PFC for a R33 into a C34. this is part of the reason Ska has a switch on the dash of his. the switch engages the A/C compressor instead of the ECU. everything else pins out and works.