I find myself liking these two which I made...
This one and
this one.
I like the second one better.
That car is a Ferrari 360 Modena Spider.
This is the original wallpaper, I stretched the background so it would fit my desktop (1280x1024) and then modded it using the GIMP (I got the Windows version- they "recently" ported it for windows from Linux). I think the edits came out nicely. I didn't stretch the entire thing to fit 1280x1024 because it was originally 4:3 but 1280x1024 is 5:4 so it would have skewed it, not to mention the ugly effects of stretching it.