My cats are a bad in my jaguar stype 2006 3.0

they are a grand a peice at jaguar.
I want to buy cheap cats..

My question is what cats are compatible? I dont know much about this topic. Can any catalytic converters work? How do i know what are compatible? Has anyone put diff cats on their jag?
Info please

As I understand it (I'm in UK though!), in CA you need specific cats but you'll still have a choice and do not need to use a dealer, which will save you lots of $$$. Online places may let you search but see if others post suitable info.

Also... try to find out why one or both need changing because that's fairly rare and often means the car isn't running quite right. A cheap OBD tool like elm327 will let you find out (look at fuel trims with live data). $10-$50.