I would say that this is probably the BEST all around combo you can find. You will need a clutch to ge the power down (Try a SBC Con OFE or FE)
The only thing I would do differently is go a little bigger on the injectors. Try the Mach 3s first. Since you only tow 4K, AND you have a turbo in the package, these injectors would be completely safe. You can run a Mach 3 in the combo with the stock turbo, though you will get very hot with the box turned up.
Since you have a B1 in the mix, I would personally go with a Mach 3. 5 or Mach 4 and leave the box at the lower levels. Let the injectors do most of the work.
PMAX comp/EDM Mach 4s/ B1 turbo... that's an EASY 500 hp that's streetable too (though at high elevation you will get some off-boost smoke). Unfortunately, your nearing (or at) the limit of the stock headgasket.
So, if you are lower elevation, go with the Mach 3. 5 or Mach 4s. If you have resevations, or have to tow heavy (or want to play it safe) then go with the Mach 3s.
I WOULD HIGHLY DISCOURAGE STACKING AN EZ. There's simply too much timing for that amount of HP, and the marginal decrease in EGT (and slightly enhanced bottom end) is NOT worth hurting your engine. Some others will disagree with me, but I think many people (including me right now) are running overadvanced timing. The Edge boxes are just a little PAST the "Edge" in that area.
Go with the PMAX, EDMs and the B1-- there's not really much you can do to improve on that.
Justin