The car is tuned for the parts that are on it . If u start swapping parts and its not going to run right . Also just cuz u clear the ecu with a buddies accesport does not mean its going to put the stock map back on . You would have to have the stock map flashed back on . Thn if u did do all that u would need a tune anyways if your going to keep the exhaust and inlet and such . So your not really doing yourself any good . If its running good and you aren't going to be able to afford having it retuned then id say leave it alone.