Re watermark.
Well then, I stand corrected. I see quite a few amazing images without watermark. Now, granted I dont make any money from photography, and therefore my perspective may be different. I have done a few free prints for friends, and even a couple for perfect strangers of some of my images. When I post and display my images I am hoping those who see it, enjoy it, and a watermark in the middle of image would ruin it for most people. I also find it presumptive and accusatory on my part to include the watermark.
Shame on the person who stole your picture of the Porsche. I would contact the company that is distributing the flier, if the resemblance is obvious. although, an image google for Porsche, yielded more than 32 million images, and in the first couple of pages I dont see any of them with watermarks.
My opinion of course.