Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.
I'd suggest NOT using auto.
don't under estimate a zoom lens I find the zoom lens's take a better quality photo for the type of shots that I take.
Mate you only need something like the Canon 400D or equivalent with a wide angle lens of some type possibly an L series lens I have a 400D + a 1D markII (professional body $5000 new now discontinued) with the canon 17-40mm f4.0L series lens and it takes some great pics of cars but don't under estimate a zoom lens I find the zoom lens's take a better quality photo for the type of shots that I take.
Take photos at sunrise or sunset for the best light, if you have to shoot in direct sunlight use the flash to even out the light. Take photos on the side where the light is.