I’ve always been puzzled how front/back brake balance is maintained when a different size caliper & rotor is installed - not that I would claim to know a lot about brakes.

 

I am fairly sure the 376 mm rears have very little if any greater stopping power than the 326/325 rears.
They have almost identical pad area and very similar rotor braking surface area (the 376 mm brakes have a yuge central blank area).
Other than the improvement in looks (my main reason for changing over) the only difference I can guess at is the larger brakes would be less susceptible to fade, which of course is only a factor under severe and protracted braking such as at a track day.
In the thread I started about the rear brake upgrade a few early posters suggested that I might need to get the ABS recalibrated but I never bothered with this and I have never had any problem with the brakes. I also suspect the OEM brake balance system/calibration easily and automatically adjusts for any slight increase in rear braking power.

 

Keep in mind that stopping power is a function of clamping force x effective radius. If you take the same pad/caliper combination and apply it to a larger diameter rotor, you increase the effective radius and braking torque. The change from 325 mm to 376 mm rotors will yield ~15% more stopping power just due to the effective radius change. As mentioned, you also have the benefit of more mass and area to absorb and dissipate heat for more braking endurance.

 

Am aware. I can lock up the rears on the street with 305 rubber at will now...so unless I am doing "track" the larger rears at 9.5lbs more are not likely helpful, and even then the fronts are doing 90+ percent of the work. The 326mm rotors are larger than the 996 rears I had on a 700hp car that got tracked and I did not lack in stopping power...issues were front temps....never the rears....at VIR.