damn, somebody kill this Gremlin...
http://72.35.72.219/~library/16285/OBD%20codes.htmread this GJ, maybe it helps.
possible causes
Pinched, shorted, and corroded wiring and pins
Crossed sensor wires
Exhaust leaks
Contaminated or damaged sensor
i don't know if these are irrelevant, but it seems that there are codes from the intake, to the turbo and then the exhaust...
either things are crashing for some reason, or because of the malfunction of one, the other(s) show malfuntction too.
i would start from the tuners advice, then i would replace the maf, the bypass valve and the O2 sensor.
if not under warranty, i believe these three would costa around $200-300 all.
this way you can eliminate (or not) the cause that these are bad stuff that causing the problems