Thats a good question. I do know that they have a different
FEEL to them than the regular DTS.
But as to if they are larger of different.. I can't say.
I will say that I have done some very
SPIRITED driving in the mountains of Colorado and have never had any problem with brake fade.
I wasn't power sliding around corners like I have in 'Vettes but I was running it pretty hard. Was playing with a Z28 Camaro. I could actually outbrake him on curves and corners thanks to StabilaTrac and the Magnetic Ride control.

I passed him on the inside of a curve after outbraking him coming into it. The back of the Camaro kept getting loose on him on hard braking.
After several miles I got
"THE LOOK" from Darling Wife and waved him on around and let him go.
He saluted me and tipped his hat.

I think he respected the Caddy a little more after that.
The brakes are very good.
I would
NEVER had tried any of that in a regular DTS. There is a
WORLD of difference between the regular DTS and the Performance Sedan.
Texas Jim