If you can skid the front tires with the smaller disc then the bigger unit is just not worth the effort, IMO. Every day driving, especially on a lighter A body, never gonna notice and I've driven both set ups as well.
If you plan on beating the snot out of the car running autoX, etc, then the big brakes are useful from a heat dissipation standpoint.
IMO, it's more about I got this big brake set up then it is about utility in most cases. Much like most of the guys that I know who installed rear disc... Most don't ever use them to their full potential. It's eye candy and ego.
For me, if I can find a complete set up with a 10.87 rotor that needs maybe a turn, that's a better value than another $100+ in brackets and 100-150 in new rotors on a daily driver.
Like I always say... Pick your parts, Pay your money!