I would suggest the use of a heat gun and installing the additional shim for the break in period. My 5 port turbo was extremely tight when new and still remains very tight. The heat gun will loosen the engine up making it easier to start and save your rod from any excessive wear. I am having better luck with os p3 plugs, odo 97t's dont seem hot enough. I have about 1.5 gallons through my motor and things are definitely coming around, better temps, more power, and better fuel economy. So far I am very pleased with my go engine and plan on putting another one in my soon to arrive mbx5t.