[THE NEW GUY]

I can still feel some hesitation but I think it's the original performace of this engine with stock ecu chip and 87 octanes gasoline.
You all are rigth about the MAF readings: The outback MAF have a diameter reducer on the plastic mold right before the sensor. It speeds up the air flow so it is reading more air than before; but I think the O2 sensors are doing their work by reducing injection duty time. At high rpms, performance is noticeable poorer than before. I've never reach fuel cut off point with my SVX, so I don't know how the reading are but I can try reading voltage and check what rpms correspond to 5v with this outback MAF.
I insist: even if I make the mix richer wit the outback MAF the O2 sensors will tell the ecu to reduce the duty of the injectors and will compensate to keep stechiometry, rigth? Is this correction fast enought?
I'll resolder the SVX MAF tonight. Let see if I can post some pics.