Just a note on the comparison tests magazines or show will produce. Car makers will usually lend a car for the test, and most of the time they "cheat" a little. Either with semi slick tyres, or an opened up engine... In France they compared the Mc and 458 on 2 tracks, small track and big track. Results were Mc faster on track with longer strait and slower on track with most curves.
One fun point is that on a big performance comparison test with mid engined supercars, Audi sent an R8 with 20 000 km on it! while all the others were brand new. Gotta have faith in their products