Had a few minutes so here you go "LEARN"!

 

Interestingly enough multiple studies have shown 45mph is the sweet spot for the majority of vehicles.
Even with a host of variables like how many widows open versus the AC settings, etc. etc.
Using AC can increase your fuel consumption by as much as 10% but opening the windows at higher speeds can increase fuel consumption by as much as 20%.
Generally speaking, below 45 degrees open your windows above 45 degrees use your AC.
Exception is Hybrid vehicles as any AC use at any speed severely impacts their mileage.

 

The internet seldom has empirical data about that and each model on any given platform has different aerodynamics and never account for driver interaction
I would guess most of those copied internet information came about in 1974 and we all know (a majority of us) why.
I can suggest that those have instant MPG (better to combine that with TP % monitoring) that they can look at the effects of MPG vs throttle interaction and get a better idea of where their sweet spot is for best MPG vs MPH
The BIG variable is each drivers , driving habits.

 

Personally, I don't see any noticeable MPG change (using the onboard monitor) with open windows in the summer to closed windows in the winter or the few times I ever use my AC.
If you're into it you can use the drag formula
Fad = 0.5 · Cd · A · ρair · v2

Or for those less math/physics inclined and have a bunch of free time like this retired guy, HP Wizard has a pretty good tool for figuring out vehicle aerodynamics.
I'm not boring by choice I just can no longer physically ride a motorcycle or use launch and load a boat.
Had to fill the time with something else as I can only play so many video games and guitars a day...
Vehicle aerodynamics

 

The speed and condition is for example only. Thier are more variables but taking a cell phone picture holding the camara and setting the speed manually safely is a fun challenge.
Cruise control tends to show lower overall MPG then what I can achieve manually adjusting the drive by wire for the changing road conditions.

My friend that is an actual "rock scientist" was able to allow me to take a vehicle I was developing a wing for in the wind tunnel at a science lab here in CA. I was interestingly amazed that the formulas for aero dynamic in real world testing are so vastly different. Nuff said. I got the wig developed and it work and have sold several dozen worldwide and made enough in the end to buy a meal a Taco bell. LOL
My lesson learned from hi is that if formulas were absolute then test and developing anything would be absolute but they are flawed when it comes to nature. I should mention that this is also why when I install a hood scoop I do stick, clay and ribbon testing at various speeds because again the aero formulas don't work having to do with air flow in the real world. Only give a starting point.

 

Like everything else in the world, formulas and testing methods are only as good as skills of the person doing them, or lack thereof.
We, at least those my age, have all been the recipient of both extremes and I personally overestimated my own abilities in engineering, math and aerodynamics on multiple occasions. Thankfully none of which killed me or others but did result in great bodily harm to myself as x-rays of my skeleton will attest too...

 

LOL are we going to compare Terminator objects in our bodies next... LOL
What I learned in college on my final in in physics class was to wear your helmet and tuck -and-roll . Oh and keep your limbs close when ejected from your bike @ high(in excess of 100mph) speed velocities. LOL
For me I am like Patrick Swayze in road house wherever I go I keep a complete copy of my medical record including all the x-rays... LOL

 

Yup it’s a great engine

 

2.5 NA far underappreciated - agree 100%-

 

Yes it is.
And it is easy enough to exceed the power rated for at least the automatic transmission they come with. Good luck if you can find that info but a few of us did testing and know approx. were that number is.
This is also interesting because of Mazda's claimed power rating for Turbo engines would 'break" the automictic transmissions. makes you wonder a few things.
But then Mazda ( like most auto manufactures) does not participate in certifying the actual power of the engines under the document SAE J2723 specifies the procedure to be used for a manufacturer to certify the net power and torque rating of a production engine according to SAE J1349® or the gross engine power of a production engine according to SAE J1995®