Oh, I forgot to add a little blurb on compression. The VQ35DE runs a 10.3:1 compression ratio. If you want to boost higher than about 10 psi, you had better drop your compression to 8.5:1; in other words redo your internals with new rods, pistons, and valves.
The compression for the stock VG30DETT is 8.5:1. That one runs easily on 14.5 to 15 psi of boost, and you can probably safely run it a bit higher (around 18) on pump gas. The GReddy PRofec-B boost controller on my 300ZX TT allows me to run around town on low boost, and if I want to light the afterburners, I just punch up high boost. It's a really good solution to reducing wear and tear on your engine, while still having heavy duty horsepower instantly available.
And why are the Japanese switching over to superchargers on the VQ35? One look at a comparative torque curve might give you the answer. My torque shoots right up at 3,000 rpm and stays solid all the way to 6,000 rpm. The typical turbo torque curve is slow to rise and drops off rapidly. That's why I can spin my 350's wheels at 90 mph. Although my 300ZX is pretty comparable in horsepower (about 15 less) to the 350Z, there's no way it has enough torque to do that.