HP is torque with a multiplication factor.
As for low comp/high boost.
I take it you have never driven a 6.5/7:1 comp turbo car.
they are crap.
As for more boost means more torque...well yes and no.
Boost is just inlet restriction, say 1 car is running 25psi with a dead standard Rb25 and makes 500hp, then another car with the same turbo but has cams and headwork is also making 500hp but only needs 20psi to do so.
You mentioned VE and that is how efficent the engine is, the more efficient the head(s) the more power you will make (given the turbo can flow enough air in your application)
My way of thinking is, a turbo is just the air pump (sure there are good and bad ones) but its not the be all and end all of making power.
So I wouldnt be spending all my cash on just a turbo and injectors and a tune.
Find a turbo that flow the air you need and then spend some coin on the head, I give no shit that the standard head and cams in a 25 can flow 375rwkws...its pushing shit uphill to do so.
TL;DR make the engine more efficent and the power will come no matter what turbo you have.