I love mine and have had no problems. sell several of them every week. The funny thing is when there compared to the Vitos head. lol. There the same head. I like the one piece design, no need to change head studs and the fact that theres 33% more coolant capacity. If you need to use a little somthin extra to seal it, so be it. Big deal. Your still in it for less than a new pro design. Once you Buy the orings, head studs and domes your in it over $300. Far more than a complete modquad setup, with domes. Oh ya, just my .02. lol.