Uh... I guess you could change that by altering the shape of the turbine housing, but I don't think it would make more than a few rpms difference in your spool time. "Spool" refers to the turbine starting to build positive pressure, not a certain physical part of the turbocharger, by the way.
he said and HKS said you need to modify the exhaust port where the exhaust air is blowing on the turbine. They put this traingular object or something and would cause the flow angle to blow on the turbine. somethin like that, but i'm not sure though. his t3/t4 runs very different from others.
To change the way the exhaust flow hit the turbine would mean a new manifold with a different shape to it i.e. short runners, equal length, or long tube.
If you want to reduce lag then go with a short runner setup, for better bottom end go with long tube.
As for modifying the turbo its self good luck! You can go at you turbo with a saw and welder and let me know how that goes, I am sure the guys that make the trubo's are a lot smarter than your buddy
if he's referring to wastegate position, this is very true. it should be angled slightly down.
in other words, drag's manifold blows ass- the gate stands straight up
rev hard's manifold blows ass- the gate stands up and sideways
inline pro's manifold blows ass- the gate stands straight up