If you go to Syty.net and look at the ecm threads, you will see that there isn't much that this ecm can't do. Several have sold their FAST systems and returned to the stock ecm.
Yes you can use wide band, you can also get a patch that allows use of a 3 bar map.....which allows the ecm to see/interpret/react to boost levels over 14.7psi. This ecm works just like any other GM ecm, its just spped density vs map. The main reason we have chosen to use it over the buick version was that we already had the tuning tools for this set-up, and we had a ton of MAF problems. Plus, Jeff(typhoon) and I tend to have ADD and are not happy unless there are parts/wires/etc hanging off the car. There is another board member here that has been runing this ecm for quite some time, with 60 lb injectors and he has had excellent results.
The tuning is slow right now...other obligations have come up, and the car has become the "only" daily driver. I have actually offered to pay to dyno the thing myself, and he still won't turn the boost up to 15 psi. All I can tell you at this point is that even woth a few minor issues (a little rich at times) this thing is exponentially better than it has ever been before.
we talked about it for a while last night , and the general plan isthat as soon as this is not his only good transportation, the wick will be turned up and the dyno numbers will follow.
as far as streetability...we have several thousand on this setup, and it is better than ever.