I recently had the mass airflow sensor replace by a local garage on my 2002 Pontiac Grand Prix. I was looking at replacement parts online, and they seemed to be significantly cheaper than what they charged me for the part. When I asked them about the price difference they told me that they used the manufacturer's part (I think the term they used was "OMC") instead of using an after-market part, because the after-market sensor would probably only last a few months anyway. Is this true? And how much should this part have cost me if it really was the manufacturer's and not an after-market part?