you NEED aftermarket head bolts. ARP. They are longer. You will crack the block without them, it's just a matter of time. You are allowed 0.004" warpage on the head. If it's more get the head milled flat. You need to remove the precups to do this.
99% of the time I think it is head gasket problem. Head warps more than it cracks, it is aluminum after all.Tolerance of warping is low on these beasts due to compression I think. Using the metal gaskets seems to help with that. At least those cranking their turbos up to 15-20 psi seem to like them.
...BTW your Bieber avatar is awesome.-Malone