Hi Neil;
My old stock diaphragm actuator gave me ~6psi.
However when it failed on take off, due to a burst diaphragm, the boost instantly jumped to about 16psi, which was surely an exciting event with very impressive performance. I quickly throttled back before any detonation could occur.
This is adjustable by changing the springs. And it is a piston so it won't suffer instant failure due to a burst diaphragm. It's failure mode would be due to a worn o-ring on the piston, which would show as slowly degraded control ability and would be a cheap and easy repair.
And it will save you 0.3 lbs
And it looks way cooler
It ships from Taiwan, so it's on the right side of the pond for you.
You certainly can use the stock one, but due to it's sealed design, it can't be taken apart to inspect the diaphragm and since it's located right next to an extremely hot heat source it's life time is limited. In my job as an instrument mechanic in a steam plant, I have to repair many automatic valves. We always try to avoid using diaphragm valve actuators in high heat areas, instead opting to use piston actuators. The heat can affect the o-ring on these as well, but the failure doesn't result in complete loss of control for the operator, and even if a proper rebuild kit is not readily available, a generic o-ring can be used or even make one using a splice kit and it will still give years of reliable service in some circumstances.
The only advantage to a diaphragm is response speed as it will be slightly more responsive, which could be advantageous in a street racing application, but for our use in aircraft this is of no concern.
So, yeah you can use that one, but I recommend the investment in a piston type actuator.