these cars can be hard to tune i heard. But when i got the car dynoed the guy told me the only thing you can really change is the fuel pressure. I don't really know so what else can be change to help the car run better?
With the right parts and scan tools you can change:
Boost, fuel pressure, spoolup fuel delivery on some chips, alcohol injection delivery points, timing with chips or translators, base fuel, WOT fuel.
Monitoring devices would include, scanmaster, Turbolink and laptop, Direct Scan and laptop, OTC4000, EGT meter, Fuel pressure meter, Wideband O2 meter, boost gauges.
In your case the dyno. guy was probably right with a standard chip, MAF, and simple mods. If you had an adjustable wastegate arm you could increase or lower boost depending on what your WOT A/F ratio was.