I'm now also in need of one. And this is a good question. The sensor at Advance Auto Parts is $93. With their $35 online coupon code, that makes their sensor $58 plus tax when I pick it up in the store. A savings of $42 over the Honda part would be enough for me to go aftermarket if I knew it would work. Having said that, this isn't an easy sensor to replace. And I don't want any error codes to follow my work. Hmm.I discovered my 200o Insight knock sensor broke (where plastic and metal connect). Do I have to purchase a $100. genuine Honda knock sensor, or are there cheaper alternatives out there that would work?