Hi guys. I have a 599 (obviously, thats why I'm here) and as much as I love the noise when the exhaust valves are open; under 4,000rpm it sounds like a Toyota and not very exciting. Is there a way to keep the valves open when under 4,000rpm? I took a look under the boot and noticed that the valve is open when the engine is turned off, and the valve seems to be operated by an air-hose of some kind. Is there a simple solution to keeping those valves open all the time. And would it do any harm in regards to exhaust back-pressure? Thanks in advance.