Safe chee as in I've owned a number of WRX's with increased boost, stock ECU, likewise with a number of friends of mine, that have lasted for a long period of time with no sign of trouble at all. Clear as mud?

Sure the AFR's might not be 100% perfect, but don't tell me any variation to the lean side of stoich is gonna be a killer. I think theres some room for play if your sensible.