I've been chasing what I though was a timing chain sound and after working on for what seemed forever I decided to check into the heat shields. The ones around the cats seem to be an issue as I've "pinned" a nail shank between them and the cat in spots and upon driving the car the noise stopped significantly. I don't want to drive around with nail shanks in my shields and was wondering if anyone has removed their cat shields w/o any "heat" issues. My XJS, Lincoln LS all have similar cats in similar spots w/o any shields wrapped around them.