Eh?what do want to change the ECU for if you are only changing seats and subframes?
 As far as I know the ECU will not work on another bike if it has been used.Summat to do with the chips in the keys,ignition and clocks.
 Just get a blank key cut for the seat lock,or use the "finger on the cable" trick.
 
 [Edited on 16-8-2004 by KeefyB]