The lower trim on the front bumper of the SC is a more shiney silver vs. a more darker grayish silver on the LUX.
And if I'm not mistaking, the front grille is the same shiney silver vs. darker gray (that may be wrong, correct me if it is)
This just came to mind. The tailgate strip on 2012/13 comes in 2 different colors as well. A darker and brighter. I'm not sure what the model of car Has to be before the color changes. I'm sure the supercharged and autobiography has the bright silver. The HSE LUX may have the bright silver but I'm pretty sure the regular HSE has the dark gray strip.
That's correct about the chrome tailpipes as well.
I'll try to find pictures of the different grilles and tailgate trim and post them.