I did the comparison this weekend. I have to measure my pads and rotors tomorrow.
I like ST SR34s for the track and I like them better than the Pagid Yellows as far as performance. I shaved almost 2 seconds from Sat to Sun. Some of that was my NT01s getting a little grippier. I was braking later with more confidence. They were also easier to modulate and trail brake. The pagids were grabby but as I buried they pedal, it seemed that the torque was constant. These SR34s seems to add in torque as you squeeze the pedal. I'm a PF01 fan so if you like the PF01s, then the Stoptech racing SR34s are an excellent alternative without the noise (so far).
The bad, they are super touchy when cold and on the street. Its almost undrivable in stop and go traffic for me.
I'm more concerned about wear rates though...more on that tomorrow.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red