Well I shot the images with the intent of doing some variation of hdr to combine the best of each image. then after that I superimposed the car shot at 0 exposure on a new layer and made it about 50% transparency. then I made a new layer in between the background and car layer and made it a black gradient and changed it to saturation and then just erased key areas to add highlights of color. in a nutshell thats what I did. I might try so background blurring, ive never had any good success with it though. any tips on that?