Check out this STEP by STEP Video on How to Install the C8 Corvette High Wing Spoiler if you want to do it yourself, or are a performance shop.
Per RearWheelDrive on YouTube:
Here’s another video from HorsePower Obsessed as he shows how he removes his Z51 spoiler and installs a High Wing Spoiler that he regrets not getting in the first place.
C8 Corvette High Wing Spoiler Install
Lastly, here is another video on How to Install a C8 High Wing Spoiler to give you a third perspective and approach from another YouTube channel Next-Gen Speed.