I already have Ninja 400. I'm thinking of getting a 2018 Ninja 650. I can take the Ninja 400 to 10,000 rpm, but I read that Ninja 650 max horsepower is limited to 8,000 rpm. I'd like to take the engine to 9,500 rpm, with no change to cams and valves train. I'll get custom full exhaust system, and custom ECU for this process, but wonder if the valve springs are up to the job, and if the stock cylinder head is effecient for this. I'll also get suspensions improvement, and track tyres.