Yes I am.......no change in their castings at all
to simply improve on the front braking ability GM just installed a slightly larger rotor. To do that they had to move the caliper outward to relocate it in the appropriate position for the larger rotor.
But really, when this platform 1st arrived there were droves of cars coming back to the dealers with brake issues. My 1st two GP's were no different, the cars would not stop very well in panic situations. The brakes are/were too small (front & rear rotors & rear caliper pistons), the boosters were substandard, there was an 1/8" air gap between the booster & the master cylinder pushrod, the diagonal opposed brake lines at the master sound good in theory but in a practical sense BOTH front calipers need to be driven off the same primary piston not split between the one primary & the secondary as the lines were installed, all tied together make for horrendous brakes.