I am sure it's possible to hoist that engine to the performance level of a KTM 990 without affecting gas consumption.
Yes its possible but it would be alot of work, it would cost, you'd also lose fuel consumption and reliability. 15-20hp might not sound like much but when your trying to mass produce it and make it bolt on so people dont complain about the price its a big ask and id say thats why none's done it.
eg. CBR1000RR 180hp kit cost about 1200 us and that again in labour to fit it all.