Entry #1: I really Like this. It could eb at home on the side of a truck or on a polo shirt. It's simple, professional and understated. I like the color choices as well.
Entry #3 This looks like a saw blade. Though I like the idea of the round logo and the colors are great. I also like the idea of incorporating a wave.
I really like the #4 (obviously, I have it ranked as #1) but i would like to add perhaps? It's still my favorite but what do you think about adding a line or something int he shape of the top of a sports car or something. something subtle that adds the idea of cars or something automotive to that great design.
I like what you did with entry 31. I see the wave and a bit of a car shape to it, but it looks a bit too much like a birds beak to me. Otherwise very nice