well you can usually get away with removing material on the side of the WG hole closest to the turbine inlet. what you want to do is create a kind of scoop. so that the exhaust diesnt have to turn a corner to get into the WG hole but it's actually scooped up. this usually is enough for most slightly modifyed. IF you need more then you're going to have to actually enlarge the WG hole which is very involved. removing the plug in the housing, removing the puck and arm. drilling a larger hole. installing a sleve building a new puck, you get the idea.
