first check air filters are clean and the play on shaft end that is exposed with filter off, it should spin freely and nothing should be scraping etc. the clearance and end float is small, value differs from engine to engine, i can't tell you what it should be on yours but it is generally obvious when it is too much !
unbalanced boost pressure just indicates one side is loaded more than the other, not necessarily a turbo problem. increase stick on the side with low boost pressure, it then should come up as that engine takes more of the load. if doing that just gives you dark smoke on the side you have increased then it sounds like a turbo problem.