What is this Tacoma part called??

Be careful when you order as they come in different lengths. Short ones for trucks with flares and long ones for the flare less models.

 

Vortex generator

 

This right here. My understanding is that it creates a stable vortex that stabilizes the air separating off the back of the rear fender there. Without it at high speed the air could shed from the back of the truck in an uneven oscillating pattern that maybe would feel like buffeting at highway speeds? This is my guess.

https://www.youtube.com/watch?v=4Bmhuq38EYI

 

Yes

Yes this is the same or similar explanation as in the video I posted.

If and when I install a high clearance bumper and have to cut that part of the truck off, I’ll post a review of the stability of my truck on the hiway.