I agree that is what you are selling, but you are in a marketplace that is rather diverse and includes nonconversions. So, your competition is all engine manufacturers that can satisfy the same need that your products satisfy. That may be one reason to include all engine manufacturers in the analysis.

In addition to other factors, it may just be advertising and word of mouth. Earlier, I said that I have bought engines because my friends have had good experience with the manufacturers. Its was just that simple for me. Buying something nobody had previously used or heard about wasn't going to happen.

Good luck!