Hi everyone!

We have a modded ( bolt - ons ) 03 GSR parting out to stock.

the idea is to put all mods to an RS and to swap the flashed ECU to get to the dyno for tune ?

Is that possible?

 

You'll have to either re-register the keys into the donor ecu, disable the immobilizer via ecuflash, or if you are really ghetto you can fake it out with the "correct" key.
To do that you will need to swap the immobilizer ecu as well (located below the AC), take your key and wrap the head in foil to shield the RF chip, then hold the "correct" key for the ecu head-to-head with the key that fits the car so that the immobilizer reads the donor ecus' keys' chip.

 

Thanks for complete answer, mate!