im running O.E double platinum ( so advanced auto said they were O.E ) and my gas mileage jumped way up ( 2001 VR6 ). I had a problem with my cat throwing up a code and turning the engine light on. After replacing it ( smart guy before me screwed the flange up for the previous cat ) i got an exhaust leak. long story short, i had to do a bit of spot welding and i disconnected the battery to prevent wire shorting and burning and it cleared the codes ( thats positive as well as negative for more than 30 seconds ) should work but if they problems are not fixed it will throw the codes and light back on within a day or sooner