Okay, here's my thoughts. I haven't had nearly enough track or dyno time (or money) to test the PP as I would like. I would like to convey my thoughts regarding the physics of it. First of all, I think the plate does cause a "restriction" in the air passage. I think this is why people who just bolt it on and race are not going to appreciate it. It would possibly cause a slight boost increase but moreso a flow decrease because our wastegates will compensate for the boost increase caused by the restriction. Think of a (perfect) propane or natural gas regulator for example, there is a certain amount of pressure in the line after the regulator whether gas is running into a furnace and being used or if the furnace is not running (i.e. no gas flow). The wastegate will control (for the most part) the boost level. I think some of the misconceptions are because we generally measure the boost pressure before the plate. I think Power Plate equipped engines, because of the restriction, have a lower boost pressure after the plate, but it is not discussed because as I stated, we don't generally measure the pressure after the plate (in the intake mainfold).
One of the advantages of using a turbocharger is the very low power consumption it has to operate. I read somewhere that turbos may use about 5% of the additional power they help create to compress the air. Therefore, in my opinion if you crank up the boost a little to compensate for the "restriction" you can be back at the flow levels you were at before with little consequences since a turbo is so efficient at making boost. The trick is not to think of it as running 20 psi when you have always had a good tune at 18 psi. It's not that you are increasing the boost so much as you are compensating for the "restriction".
What we have to weigh out and test is whether or not we can actually flow more air and make more power with less detonation as an end result because of the supposed equalization of the distribution of air. Or if maybe the turbo has to work too much harder to flow the same to generate positive results.
I wish I had a bunch of money I could spend testing my theory, but it will probably remain just that.
I hope you could follow all that, and I really hope I am thinking on the right track after writing all that.