Bolted up just fine after header was installed. We installed header shields before cat convertor was installed. then we layed lower cat shield on front axle then bolted cat back up. we then bolted cat shield to header shield just like it was before. There wiil be some bending to get it to fit. It is DEFINITLY NOT LOOSE! the shield near the sensor was pushed in with the help of a large long screw driver. I did some "adjusting" yesterday cause the edge of the shiled was rubbing the power steering hose.
I'm still thinking of adding a "header blanket" anyway because the sheild does not seal all the way around like before but the gap is not very large. I'm just being a bit anal about it.
There are no rattles in my install either. The difference in having the header is like night & day. I just love it. I removed my baffles from my BTG duals... boy did that get loud

NOW I KNOW WHAT THAT 3200 RPM DRONE SOUNDS LIKE!!! Oh course I put them back in. I'll just take them out for the Porky's run in April.
If you can get a lift to do this it would be much easier. if not make sure there is another to help you. Remember top header shileds screw down, cat shield bolts(nuts) up to those bolts hanging down. ( we learned the hard way )

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Cool Vanilla 04 GT 5 speed; S1, custom silencer mod, K&N drop-in, AMX1397 TTAB pipe, UCP, Ventshades, badges removed, coilovers, Mopar Stage 1 Sway bars, Freedom strut bar, PTeazer retro grill, bumperette, cowl induction hood, rollpan & other assorted painted body parts .
Member of www.mnptcruiserclub.org
MAC (Minnesota Autosports Club) Novice AutoX Day