[Keith Wagner]

Make sure any cat you get is OBD II compliant.
As for shops, there are quite a few of them in the area. I used a shop in Naperville when I did mine.

 

[Keith Wagner]

Looks to be OBD II compliant.

I have bought catalytics from a place called Airtek/ Catco in Hobart, IN. They make all kinds of emissions and exhaust parts.
They are right off of 65 and Ridge. Just something to check out.,
Can't remember any names, but I thought there was 1 or 2 good shops around Mokena-Orland-Tinley.