After thinking about this 1000 times, Tach and Sleeper did this... in the correct order... If the turbo does stress the engine a little, let it die an earlier death, then do the swap....all in all, not a bad financial option when considering trade-ins, depreciation and sales tax to try to keep up with new....... $ 42,000 plus base car cost over 5 years vs cost of 997 turbo .... all the while, dragging the tail