My truck is throwing a p420 code after a heater hose leak took out the #3 and #4 cops. I also hear a slight rattling sound coming from the exhaust.Guys on this site said my cats are toast and to replace both sides with hi flow cats. Can anyone who has had this done give me an approx price for the job? Got a quote for an oem cat for bank 1 OUCH!!!!!!!!!! Thanks in advance