Hey guys, so I have a question on whether I should replace my cat or not. I have the P0420 code and honestly probably had the code for a good two years since I bought the car( 2009 Legacy 2.5i Limited.) About 6 or so months ago, i had my car being driven by my GF and all of a sudden the car didn't accelerate like it should've and was brought to a shop and had the cat "cleaned out" not sure what they did as the question wasn't asked how it was cleaned out but it drives and accelerates fine. Im thinking of buying an axle back exhaust and was just wondering if i should get the cat fixed/replaced first or just let it be, as its not really causing me problems. FYI, this is my first car. Car is at 148k.