i recently bought my 97 a4 2.8 quattro w/ a messed up cat. he said he replaced one already and now the other one needs to be replaced. i am from california so we have to go w/ obd 2 and not obd 1 like the rest of the 49 states. i know it costs like $300 for obd 2 cat and like $50 for obd 1 so i took it to a muffler shop and asked them if i was able to put a obd 1 cat on and get away w/ it w/o setting off the check engine light. he said only if the sensor is not inside the cat. if its before or after the cat then i MAY be able to get away with it. he jacked it up and then said yea it looks like it will be okay. so i buy the obd 1 cat and get it replaced. it drives smooth and no more noise but the check engine light went on. HERE'S THE QUESTION: will this be a problem to my vehicle besides passing emissions? i will be able to pass emissions no problem so i just wanted to see if i could just go ahead and turn off the CEL or could this be a potential problem?