If you really want a "safety cushion" you can always add an adjustable fuel pressure regulator and turn it up a little across the board. I think this would be a killer stock turbo/fuel setup specially with an AFC.
: I can't wait to throw mine on the dyno and check it's a/f with the stock ECU and a little extra boost. It's pretty simple to retard our own timing, and increase fuel pressure if it shows a little lean. $600 overrated ECU, maybe.