A bar of boost on a CT9 is fairly on the money in terms of peak efficiency, any higher the unit will get outside it's comfort zone but I've seen them run.
There's a few things you need to upgrade to maintain it's lifespan and reduce the chances of engine failure.
Think of the engine as a big air pump that mixes fuel into the air then ignites it at the right time to make power.
First and foremost you need to understand that adding more air to the mixture requires you to add more fuel. If you add too much air without the required amount of fuel you will create a lean mixture. This is very bad for the engine as a lean mixture creates a fast, unpredictable explosion which can go off too soon and hit the piston on the way up. Think of throwing a cup of fuel onto an open fire - big flash and instant reaction.
So before we add too much boost you need to have the fuel to support it and maintain a good, safe mixture.
Worth mentioning at this point that adding too much fuel can offer problems too. Say your mixture is at the opposite end and is too rich. The explosion is now slower and nowhere near as powerful. Think of throwing a full bucket of fuel onto an open fire - it dampens down first then burns once it's settled down with little flash.
The mixture is key. Too rich and you lose power or experience borewash (you can google that bit). Too lean and you start melting pistons and exploding rings with detonation/knock. So it's important you understand this before taking away the factory safety net of fuel-cut. I've seen a lot of folks fit a FCD, turn up the boost then suffer engine failure without realizing why. Some of them proceed to blow up another one or two engines before catching on.
Hey jay hope you got my pm