Ok well I finally got my headers installed and I went to take it out for a little test drive today and as soon as I started it up it began vibrating pretty bad. The vibrations were so bad that I didn't gas it over half throttle for fear of breaking something. There is also a rattling noise which sounds like it's either coming from the cat or the heatshield above it. Could the cat hitting the heat shielding actually cause such a bad vibration? Another thing I noticed is that the front O2 is resting on two unknown metal lines, but idk if that's the cause of the vibration either. I would jack it up and check out what's going on underneath but it's raining/snowing out.
Anyone have any ideas? I swear I have the worst luck with cars.