Yeah you should still pass smog. The jet valves are bypassed on half the 2.0's still on the road anyways.
To answer your original question, yes, many of us have experienced cracked heads. These motors are notorious for it. In fact, the jet valves themselves seem to be a large cause of it. Something about a steel slug expanding in a hot chunk of aluminium.
I'm pretty sure rule number one with these motors is don't over heat them... haha
Good luck and have fun with it. These trucks are addicting and there are many of us that'd kill for one with that low of miles.
~Mandle