tuning a boosted motor includes reprogramming the ECU so you can adjust air fuel mixture, adjusting the boost to an appropriate level. Theres a lot of other stuff that you have to do that i cant think of off the top of my head. I do know it requires a lot of time on a dyno. A tuned turboed motor will run faster than the same motor with the same turbo setup that is not tuned. Boost controllers and aftermarket ECU's are almost essential to the longevity and performance of a boosted motor. I guess if you want to include the upgrading the internals in tuning, thats another thing you have to do if you want to run higher boost numbers.
If you want to go turbo and you want to be cheap about it, plan on blowing your sh!t up. You just cant cut corners.