You need to compare your Tahoe to a regular one. You'll find a lot of aero tweaks have been done. So the small stuff has already been done. I'll google, see if I can find a list of differences.
Edit:
Fist find, the GM list:
Aerodynamically enhanced exterior:
Aluminum hood and liftgate
Lowered front air dam
Aerodynamic assist steps
New rear fascia, rear spoiler and D-pillar appliqués for aero improvements
Lightweight aerodynamic aluminum wheels
Low rolling-resistance tires
I know that's not a complete list, as I know the panels above the taillights are unique, and not listed.
Should be able to find the Cd improvement too...
edit:
Looks like .379 to .360 And aero mirrors are mentioned.
https://gmauthority.com/blog/2010/06...g-coefficient/