Do your homework son, you need to go on Amazon.com and purchase all the turbo performance manuals you can afford. Then you can answer your own question. It really depends on how you plan to drive the car. IE, autocross, straight line rocket, or street cruiser etc, etc.
They hide the information in books, I know it sucks, so start reading! After you get done reading all the tech books you will find most of these aftermarket turbo companies, just bairly know what the heck they're doing.