[kach22i]

I'd be more than curious about the rear spoiler delete, who told you all it did was keep the rear window clean?

The gaffing tape I tried one didn't hold up to water very well (wet Michigan), lasted maybe a week on my truck. Foil tape lasted much longer but was a terrible look.

Nice work, thanks for posting.

Any plans for a full belly pan?

EDIT-1

2008
Spoiler Alert: Minivans and SUVs Could Become More Fuel Efficient
https://www.treehugger.com/cars/spoi...efficient.html

A specially designed rear spoiler could increase the fuel efficiency of minivans and SUVs, according to a new study detailed in Green Car Congress. The study reveals that such a spoiler could both reduce drag and nearly eliminate aerodynamic lift—effectively saving several miles per gallon worth of gas consumption. The researchers used principles of fluid dynamics and ran numerical simulations in order to craft an ideal design for a spoiler specifically designed for bluff-backed vehicles. The study was published in the International Journal of Vehicle Design, and it found "that the aerodynamic drag and lift on a mini-van moving at 108 kph (67 mph) are reduced by 5% and more than 100%, respectively, when the new spoiler is attached to it."

"Conventional spoilers resemble an inverted plane wing and generally work by increasing the downward force on the back of the vehicle as well as improving the flow of air across the bluff rear. The new rear spoiler resembles a wave in profile rather than a wing."

I'm not sure what category your rear spoiler falls under, some A/B testing may be warranted.

EDIT-2

2017
Spoiler Alert: Audi Patents a Sliding Wing to Improve Aerodynamics
https://www.autoguide.com/auto-news/...odynamics.html

Audi has designed this new system to improve aerodynamics on SUVs by eliminating “flow separation,” a disturbance in airflow that increases drag which usually takes place about half way down the rear window. To fight this, the movable spoiler will lower at speeds over 80 km/h (49 mph) to the right height to combat this added drag.

EDIT-3

I was thinking at least a clean sharp edge for the air to release from is a consideration, similar to the below.

Bizon Truck Cab Spoiler
https://www.realtruck.com/bizon-truck-cab-spoiler/

It's a snap to add a spoiler to your truck. Bizon designed their cab spoiler to install without any cutting or drilling. it has pre-applied 3M automotive tape, the same stuff that holds on a lot of the factory trim & badging. All you need to do is make sure the area is cleaned well with rubbing alcohol, peel, and stick.

Done!