Replaced all 02 sensors, still getting CEL. Aftermarket exhaust?
 

I recently replaced all of my 02 sensors after getting a persistent CEL before and after installing an aftermarket exhaust/headers. The CEL semed to light up when going over a bump in the road which made me wonder if there was a wiring issue. Since replacing the 02's no more CEL for months...
But once again I get CEL (0133 "02 sensor CKT slow response Bank 1 sensor 1" and 1275 "Manufacturer control. Fuel air metering"). A day later, after very heavy rains, the exhaust starts making that frapping sound like a leaky or cracked cat. Otherwise it idles fine. Does this sound like the CEL's and possibly damaged cat are related? I have an appointment for service next week.