The 650s will come with custom tires from Pirelli named the MC1.

I don't know much about these tires except that they are STICKY!!

As long as it lets us push it to it's full potential then i'll have no problem, McLaren seems to be good with that so I'll have no worries with these.

These are the same tires as the 12c I believe.

At least if they are we can go back to that and see how well they performed, these should at least complement the performance on the 650S

I haven't found any reviews for the MC1 tires but it seems like most 12c owners are happy. But when it comes time to replace them they do look at other options just because the MC1s are overpriced.

Yup.
Plus a lot of 12C's from what I've noticed dont even hit the track so a lot of people haven't really pushed these too much.

I've seen some 12cs at the local track. There aren't very many of them so I wouldn't say they dont track them.