Thank you! Safe to assume that the output of the 2004 is the same as the MY01 referenced?
I'd translated the Japanese wiki page as well and was puzzled by the reference to CNG. The car clearly runs on petrol.
I'm in Nairobi so have limited options for doing extensive work on the car, as much as I'd like to. I may just stick with an ECU upgrade and be done with it. I'd welcome suggestions for ECU mods that a hack like myself can install without breaking anything.