Why do they have 2 different wings for the C7 2018 Corvette ZR1 ?

I'm usually not fond of big wings, but I think the bottom picture suits it more. That being said, maybe they're testing both wings to see which yields better results and they'll stick with one ?

Being the last year of the C7 maybe they're trying to make it special with a trim that sits above the ZR1, like a ZR1 _______

If that is true then there should be other differences we should be able to spot now and in the coming weeks as we get to see more.

The top picture has some things sticking out of the rear bumper. Sensors for testing I assume ?

Like a ZR1x model or something ? That would be a game changer. Or something like a strictly track oriented ZR1... I think that's asking for too much now though.