Re: '03 954 ECU BRAIN
And 929 ECU's aren't compatible with 954 harness connectors - although it's probably possible to make it work if you're happy to re-wire the connectors.
If you want to run the 954 ECU then you'll probably want to replace the entire harness and any other electrics that are wired differently.
Is the bike performing poorly with the 929 ECU?
"I won't forget that ride for a while. Maybe you're right. Living fast might be worth the final crash. Maybe that's the secret you fliers know." - Flight of the Intruder