ughhh its very hard to get people to understand i refered to my tuner that builds dsm race motor 2.0 for a living and he recommends nothing less than .005 piston to wall unless running factory setup cause the pistons are designed for stock application not for higher hp goals if you plan on reving higher than red line and running 500hp 600hp engine you definitly need looser P/W as soon as that piston starts heating up from that boost its bad news.