Keep burning up drivers side CAT

[worksneaker]

I have a 1999 Cobra with a Procharger running at 6 psi and hihgh flow Magnaflow 2 1/2 " CAT midpipes feeding Flowmaster 4 " Cat backs. The car originally came form another state and the previous ownerhad eliminated the Cats but I needed to put them back for Maryland. The drivers side Cat blew out the brick after 100 miles or so. I put another on and the same thing happened. After looking into it more closely it appears that the drivers side cylinders are running richer than the passenger side...the CAT is much hotter to the touch on that side. I checked the plugs and they look good. Any ideas???