tuning these engines is pretty useless , their gearboxes either MT or AT are the achilles heel .
i would get a bigger turbo if you really want to anyway . for the same amount of air it doesnt put in as much heat as the stock one . if an aftermarket turbo is available .
and you cant leave charge pressure out of the equation , just putting rpm and engine into it doenst make sense at all
maybe maybe, but if the gearbox is ok and not damaged, you can handle it. i dont´t want to take all the power in the first 2 gears. 
if the turbo get damaged, i will get one at the aftermarket. 
Und um den Wassergekühlten ging es ja nicht.
ich weiß das die Teile identiosch sind