40d works. Half the people I know with nice cameras, don't even know how to operate them...thus, someone who knows what they are doing can still put the 40d to good use. I use the D3000 and haven't found myself to be limited from it yet. I recommend getting a 55-200 lens too, you'll love it, and throw on a polarized filter while you're at it to reduce glare.
I use a walmart tripod too, but i just set the timer to 2 or 5 secs to allow time for the tripod/camera assembly to quit shaking/trembling after i press the shutter. This also allows me to set the ISO lower.
I'm not sure how I feel about the round PIAA...your other option also is sticking GT foglamps in the "vents" of the bumper.
Bryan