i have the same heads. i have no idea, but have to say mine were bought in the 2004 period as well. at this point i think i have about 8k miles on the engine, (about to be 9k for spring fling).

but what can you do? it definitely seems to me so far that although people have seen otherwise, the overall rumor is that if they are going to fall out, it will be right away.

if i had that happen, all i could do is park the car for now, no matter how minimal the damage was. since there is no way to check to see if anything is up with the seats, i'm just going to drive it.

oh, and my heads got a port and valve job 1-2k miles ago by a very good head guy, so at least he didn't notice anything suspicious.