It all depends on what size the turbo is, if its a little t3 or t25 then you will be fine with at 11 psi. Now running someone elses tune is a BAD idea, there are so many factors that could change the tune from one car to another that you would be taking a big risk running his tune. Also, i dont get the feeling that you know to much about boosting a car, and that will result in you turning your motor into a paper weight in no time. I would do some research on boosting before you jump into the deep end and find out you cant swim. Post up a link or get a detailed list of the turbo kit he is trying to sell and ill let you know if you should consider it or get something else