I just picked up an 04 GT 133k miles last week. Got it for a steal, but it was throwing codes for the cats. Ordered a Summit O/R H pipe for it and put it on yesterday, and it's running much better now. But the only issue I'm having is that on acceleration it has a pretty loud ticking noise, which gets louder the harder you get on it. I've done some searching and it seems like most of these cars have a ticking at idle, as does mine. But it sounds like it goes away for most people above idle. Is this sound normal and being magnified by not having cats, or is it something I should be worried about?