If it's only the boot, clean, re grease & reboot.
Even if it makes a little clicking on sharp turns, you are better off doing the same.
OEM are NLA , but keep your eyes open for used OEM ones. The ends are painted dark green.
Aftermarket are junk, don't waste your time.
More parts for these models are NLA also, so be ready to be creative / stock up on parts when you come across them / have a backup car.
The link below is not a direct answer to reducing the heat from the cat - it is a side effect of my redesigned exhaust system, however.
http://www.dynahoedave.co.nf/exhaust.html