im actually using the V4 ecu from Mtech automotive,

but if I was buying stuff again I would use omex or similar. something more people are happy to map.
I only used that ecu as it was the closest place to me that did mapping down on the south coast that I knew about at the time.

the BOA/BOB will take around 10psi with standard internals giving between 300 & 350 depending on your install.
if you have a good mapper I have heard if you back off the ignition around peak torque you can then increase it again and then push the power closer to 400bhp. its all about detonation. get any detonation and the standard pistons will just melt, and by reducing the ignition at peak torque it will reduce the cylinder pressure and reduce the detonation.