Ideally you'd want as high of a compression ratio as possible, but an even longer expansion ratio to match it. Your compression ratio is very high, but it's a "diminishing returns" sort of thing. It is possible that your raised compression isn't doing as much good for efficiency as reducing the amount of air taken in, and then using more of the pressure that your fuel gets you. If I'm not mistaken your compression ratio is more than high enough to ensure great combustion efficiency, especially with forced induction.
The turbine is not efficient, but it can pick up the leftover pressure in the cylinder that your pistons didn't collect. What reducing dynamic compression will do is reduce the amount of air your cylinders get, and increasing the ratio of piston work to turbine work.
This is especially relevant when you are giving the engine a lot of boost, because the more you boost it, the more energy there is leftover that the piston cannot absorb, and the turbine cannot absorb because it doesn't need all that power to compress the intake air.
Kind of like Miller cycle gasoline engine, but turbo driven.
By the way, it's cool to see all your mods
Must be exciting working on that.