Okay, let me type this in a way that's more likely to get through to you:
No one is even talking about FM4 so why you're grasping at that is beyond me, and your tirade about skies is quite frankly a mixed bag because you can produce photos from GT5, FM3, and even GT4 where the skies aren't as pigmented but that's neither here nor there. The point which you've got, two, three other people telling you as well is that the edges of the smoke surrounding the vehicle will result in a jagged/pixelated area. There is no "only if you're a bad photographer" or some other random, inconclusive excuse. You either edit the image once you've gotten it to your computer, host it on an image website (which, and you may find this hard to believe, applies minimal postprocessing efforts once you've resized an image), or you go through the pre-determined angles in the game (or find your own) where the obscenity is omitted from the rest of the image. Oh, and another thing I've forgotten: you could focus on another part of the car (especially if you're taking an action shot) which would essentially go right back to omitting the obscenity from the rest of the image, or you can apply a filter (cross processing works rather well at times) which, again, goes right back to omitting the obscenity from the rest of the image.
Simple as.