I would also recommend sticking with the recirc type units.
I used to have a TurboXS TypeH, but sold it within a month after having part-throttle problems.
I have also seen others at an autocross have the same problems at part throttle.
I should mention that, using the TypeH BOV, holding it at part throttle, with the engine bucking somewhat, my car actually went into limp home mode. I should mention that I was not being hard on the car at the time - I was simply holding the car at the point where the problem existed. After about five to seven seconds, I got a flashing CEL and the car would barely move under it's own weight.
Stick with a recirc unit.