And that 'servo looking thingie' off of the left side is the wastegate control.... you'll need to see where that limits and change to accomodate your lower boost level. Basically, put low pressure air into the port with a very accurate pressure gauge, and see at what pressure the rod out the back starts to move. You can mod these by taking the cover off CAREFULLY (so you can re-crimp it on later) and lighten the spring to go lower. Or find another one for a lower boost pressure....
I assume this one has 2 water cooling ports? (Probably for banjop type connections. ) And an oil pressure port with oil drain? Make sure you put a 1/2" or 5/8" ID drain hose on the oil drain side to the pan, and use a braided oil pressure line on the oil pressure side; solid steel lines tend to crack with the vibration and expansion.