I would think that you would want to be able to set the pressure the WI starts at and the volume that is added, kind of like a fuel computer.
You definitely don't need it at near stock boost levels, so you don't want to be draining the tank unnecessarily.
I haven'tchcked into what is out there, but would ? why you feel you need it - a good aftermarket system will supply enogh fuel to prevent detonation.
Now if you're heading into 20+ lbs of boost, I could see the need.
The money a good setup would cost would be better spent on MSnS and possibly bigger injectors - you'll have the advantage of losing the AFM and much better throttle/boost response. Even retaining the stock injectors you will be better off until you want more than ~260 HP.
I am of couse assuming that you are running the stock computer here from looking at your previous posts.
This is JMHO. You can buy the MS prebuilt for $200. With the results mobythevan has had, I see no reason to do WI until all the fuel issues are resolved due to the limitaions of the stock setup.
In the book Turbocharging by Hugh MacInnes, there are definite pros to WI, but the ability to tune the fuel was just as important. That along with the fact that if you are relying on the WI to prevent detonation and you happen to run out at the wrong time, you may fry the engine. I would rather look at WI as a way of keeping the combustion chambers clean...