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Thing to realise is that what generates power, is oxygen. It burns with petrol in 14.7:1 ratio for maximum BMEP (cylinder pressure). Any more or any less than that and you don't get complete combustion. But, in practice, it's 13.5:1 AFR that yields most power with some extra fuel to ensure that all oxygen molecules are burnt.
Thing is, fuel is easy because it's required in much smaller amounts than oxygen. From factory, these bikes run super-rich in WOT/upper-RPMs, something like 10.0:1 AFR which is maximum 5-gas analysers can record on dyno. So most likely it's even richer than that! Every single bike I've ever dyno-tested, over 30 different models, have always been too rich. So... to make more power, you just remove fuel and add oxygen. Remember that '60s hot-rod saying, it's still as true today as it was back then.
Tough part is getting more air/oxygen into engine. Intake side is perfecty fine without porting head and installing larger valves. Exhaust is really only place that can be improved and that requires full-exhaust. Ideally design that doesn't poke into and narrow exhaust ports, but no one makes an off-the-shelf item like that. At least full-exhaust will get you most improvement possible on this bike.
After that to increase air-flow and more oxygen into cylinders, you gotta put in bigger pistons and valves.
More fuel without increasing air-flow will just lower your power.
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