I'd remove the Mbc and just run actuator pressure, at least to see exactly what that offers. also eliminates any effect from the Mbc.
(actually I do just run this)
The stock ecu can't really handle a highflow so it is struggling, which is whats causing your problems. You need to replace the ecu or nistune it.
(i could be a little wrong as I don't have a 32, but assuming similar to 33)
running rich is good, how rich is it? sometimes in this case it runs too lean or not at all..