Its unlikely to be a boost leak as you would here it whistling on boost. They are usually quite loud.
It sounds like its on wastegate pressure, like you have a boost control issue.
Best let the professionals look at it.
Make sure you take the foreman/ workshop controller for a drive so they can experience it.

__________________
Its just the internet dude, its not real.
F.B. Racing
01 WRX (STI badged)
2010 XR5 Focus
06 Impreza Hatch 2.0i