Really enjoying your photos- the combination of lighting, artistry in the angle, and technical prowess (not to mention a truly amazing car!) is definitely an inspiration for better shots for all of us. I really need to get on my game with lighting so thanks for inspiring!
And on the technical side, for a 1 series vs. a 400d/40d/5d it really is apples and oranges. I just love picking up my mark III (though I really don't do that much these days as I am not shooting much sports) as it is a delight to hold and use. It doesn't get any better. That said, I wouldn't say it produces four times better images then a 400d- the bang for the buck you get these days from base level cameras is astounding. If you are going to spend money, spend it in lenses and lighting! It will make much more of a difference in your photos as well as the fact that these additions are outdated at a much slower pace then a new camera body. Also, you might be surprised by how much a prosumer body will take- my two year old 5d has seen everything from -20c ski races to drizzling decks of fishing boats (with some fish guts mixed in!) and has held up amazingly while producing exactly the photos that I wanted.
