Brake squeal happens on these cars. I believe it's even mentioned in the M Supplement Manual. Seems to happen most after you've heated them up and then start braking lightly, but yes as Z K mentioned above, pressing harder makes it go away. Unless you're getting constant squeaking at all ambient and brake temperatures and all levels of braking force, I'm pretty sure what you're hearing is normal.
I switched over to StopTech Street Performance pads after I got brake fade and warped rotors (or uneven pad deposits) using the stock pads at my most recent track weekend. They have the same behavior on the street in terms of noise, dust, bite when cold, etc, but they bite harder and last longer on the track. Good all-purpose pad IMHO. Remains to be seen how long they'll last, but if you're coming off Ultimate Service and can't get free OEM pads anymore, I'd consider them. HP Autowerks currently has fronts for $103.95 and rears for $79.95.
'16 Cayman GT4 (delivery pics
Gone but not forgotten:
'11.75 M3 E92 Le Mans | Black Nov w/ Alum | 6MT (owned 5/2011 - 11/2015)