My other car is a MINI!!!!
I think he's talking about the capabilities of the standard ECU Bill, not so much his current hardware.
there used to be a belief that the standard ECU couldn't be used to tune cars over a given power level, but to be honest I think that's all crap.
I'm pretty sure Bill tuned a Big turbo leon to around 460bhp on the stock ECU, and I know R-tech tuned an EFR Leon to around 440bhp on the stock ECU. Christ, Wellys car has almost nothing plugged in or working and his pre-historic ecu is working fine at 450bhp!
With bigger turbo'd I see no reason why the ECU couldn't be tuned to run 500bhp+