if one breaks his turbo engine, it is not going to be paid for by anyone's factory warrany-exactly the same situation as waiting until the factory warranty expires and then adding the turbo. Which means that waiting out the factory warranty before installing a turbo accomplishes nothing except insuring that the mechanism is one half used up pre-turbo. Furthermore, it eliminates the fun of ever owning a nice new automobile with enhanced power. It is rare for any modern automobile to have an engine/drivetrain problem within the warranty duration. Those problems that do appear are generally minor and will likely cost under a hundred dollars. To preserve the warranty for many thousands of miles to avoid a possible hundred dollar component failure rather than enjoying the extra performance seems to be the poorer choice. To assuage your concerns, call the car marker's regional office and discuss with a service rep the areas of the drivetrain that have been a warranty problem.