Well, hopefully my new header and new O2 will fix it right up. The only reason I'm pessimistic though is because I know that hairline crack has been there for a while, and I really doubt it's to blame for the sudden decline in performance. We'll see though.

Anybody else have any ideas? I'm thinking maybe I DID damage something when I hydrolocked it, it's just not showing itself until now... (???)

Another thing to note is that this hesitation/sputtering problem is at it's worse when I first start the car, then seems to get a little better after it's ran for a while. Just when I left work today to head home, I almost got in an accident because I took off right out of the parking lot, but the damn thing wouldn't hardly get going (with traffic coming) until right at the last moment. Ya, I got the finger... :S