It certainly won't be a "performance" mod. It will reduce torque below standard at lower revs.
The other thing with making the effective expansion stroke longer than the effective compression stroke (that's what happens with late intake valve closing), is that there will be less energy left in the exhaust gases to spool the turbo up.
There's a reason Mazda did this in conjunction with a supercharger rather than a turbo (on a gasoline engine). There's also a reason that they don't do it that way any more.
The non-forced-induction Atkinson cycle has the same effect; lots of hybrid cars use it; quite a number of gas engine cars with VVT use it to emulate the Atkinson cycle when running at part load. The hybrids use the electric powertrain to fill in the missing low-end torque.
diesel + atkinson/miller + turbocharging => probably not very happy.