Well I had the same squeal, I could only hear it at idle and just after letting the clutch out. Chased my tail for a little bit but I put my hand inside my right side pipe and there was my problem. The glass pack had broke the weld, come loose and pushed itself up against the curve at the outlet. My car would stumble at higher RPM and that was a mystery as well. I took a laser thermometer to my right side header at each cylinder and each was at least 100 degrees hotter than the left. When I mashed the gas it slid aft and somewhat blocked the pipe robbing my power. I pushed it all the way forward with a hammer handle and put a self tapping screw through the bottom of the pipe to hold it forward and my problems went away. There is a guy on youtube that has welded his when it came loose. I'll take mine off and get it fixed when it comes back from paint
Might be what is ailin ya.
