You do realise that motorsport and mechanical engineering are the same qualification at a higher degree level don't you?
Yep, but I presume that the desire is to find work in motorsport rather than in the general industry, and if you were looking for a job elsewhere then you'd be better off with the bit of paper that says Mech. engineering to be quite frank. I'm only forming an opinion from my own experience, and the shared opinions I have picked up. It doesn't mean that I am right.
Doesn't matter. In fact, I know of at least one large company who laughed at my dissertation supervisor (former employee) when he told them he was lecturing "Motorsport Engineering". Irrelevant of the fact that it is largely the same, to many employers it pigeon holes you into one area of engineering in their view.