I have a 93 R1. Looking to replace the ECU. I heard mazda upgraded the ECU to turn the A/C off when the clutch is depressed and when the gas pedel is released. This will cost $2700. Will an upgraded ECU do this for me, like an APEX. My car stalls when the A/C is on and at idle.

 

The ECU turns the AC off when you go WOT. I think all stock ECU's do that.
Whoever told you about the $2700 is bullshitting.
Just get a Power FC or Hatech.

 

The stalling at idle w/ the ac on is usually caused by LOW COMPRESSION or Vacuum Leaks - have a compression check done.
Very early ECU's would cause a stall when coming to a stop w/ the ac on because of bad fuel mapping for the close throttle condition - MAZDA replaced thoes ECUs for free under a recall program, check with a dealer to see if your ecu qualifies.