Not so many years ago, the only way to real performance gains was Nitrous / Turbo / or even Supercharger.
This seems to gone out of fashion with the modern set of performance bikes.
I think the new age of computerised engine management systems has made it too difficult / expensive to go down that route.
I was at the world wheely competition last year at York, and there was some serious bits of kit there.
Each to their own & this is NOT meant to be offend anyone, but if I was spending £1000 on something that was a performance up-grade, it would have to make a big difference, not just more bling & noise.