It depends on where you think the 4runner needs the power.
Procharger will make more power up top as it acts more like a turbo than an actual blower.
Magnuson will make most of its torque in the bottom and power thru out the power band and tapers off at redline.
I personally think that the magnuson would make the 4runner more of a joy to drive around town. Because it will be more responsive to the throttle input.
As for the 7psi vs 6psi ... its negligible as once it gets cooled in the air to air intercooler and travel all that way thru the charge pipes ... the 1psi difference wont make a difference. Depending on the efficiency of the intercooler that 7psi might be 6psi when it enters the intake manifold.
I hope this helps