I think the stock head works the best. I've tried the modified Airsal one, and it sucked. Like, way lower compression and 10mph slower, sucked.
And it's no me. I know what I'm doing. It's the head. Sucked.
You can run the stock head with no head gasket with no problems, it'll seal right up and give you more compression.
Oh yeah, make sure you check your head, because the original head gasket has probably become one with head, and used a cloak of invisibility to hide from you. But it's there. It's always there. Poke it with a Stanley knife and you'll see...