So here is my opinion, that 12c is modded pretty substantial, i would think it has even more than just an exhaust and flash. It's true that i never owned both cars in the same time, but the Huracan definately feels a lot faster than the 12c especially from a standstill. Even from a roll race in the worst case scenario it would have been a draw.

After having the huracan for couple of months i would never return to a 12c simply because the h suits much better my needs from a car than the mclaren. The only reason for which i would choose an 12c/650s over an h would be if i would use it a lot for track, i think in that field the mclaren could be a better option.