Welcome to the Forum!! /phpBB/images/smiles/icon_cool.gif
I'm running a Vortex on both of my Zs. I bought them because they seemed to be the best bang for the buck. You may also want to consider the Haltech/Tric system. Its a very nice looking piece. Jakes Corvettes also makes a nice intake and they have eleviated the water injestion concern with their design.
Basically they all do about the same. You just have to decide how much you want to spend.
I'm running a Halltech Tric with carbon fiber Cobra. It is a bottom-breather that puts the air filter right above the air dam. I stay out of high water. /phpBB/images/smiles/icon_smile.gif
Don't know if all the air intakes perform the same but here are my results:
The Halltech added a (before and after) SAE +10 rwhp and +15 rwtq on my car and it produced a 117.4 mph trap speed which is higher than 345 rwhp ought to make. So it seems the engine with Halltech is producing more power at speed than it does on a chasis dyno.
The Halltech also produces a wicked raspy growl at WOT that's /phpBB/images/smiles/icon_cool.gif
My suggestion is to do some searches here and over at the Corvette Forum Z06 and Tech boards and read the range of opinions.
Torch Red 2001 Z06
Delivered August 2000
Only mod: Halltech Tric with carbon fiber Cobra
Just one day at the drags: best run 12.47 @ 117.4 mph with 60 ft. time of 2.05 on stock tires
Current dyno results (SAE) 345hp 349tq
Bang for the buck for the aftermarket intakes for the LS6 is about half what it is for the LS1's due to the better breathing capabilities built into the LS6. I installed a Vortex only because I had it left over from a prior C5. It dyno'ed about 10 more hp on the LS6 where it gave the LS1 about 20 more hp.
With the water concerns and the open screens on the Z06, I'd go for a cheap solution that sits above the radiator shroud that requires no cutting. I think you'll spend less money and get just as good results without the worry of water ingestion. I'd probably go with the donaldson or just open up the stock air box.