"According to those tests, I have to come to the "possible" conclusion that there's a small iddy-biddy chance that I might have wasted $ on K&Ns over the yrs?"

Don't go bashing yourself any time soon or buying all the "conspiracy" hype that the aftermarket world placed countless products out there that just don't work. Any Google junky who never pulled a spark plug can find a test to oppose your thoughts. Look at real world as opposed to test monkies that can manipulate parameters. So called third parties who may or may not be marketing for the OEM paper crowd to regain a portion of market share. K&N has filters that NASCAR approved to run in their vehicles....so now there are a bunch of idiots who work in the professional performance world that want to install a more restrictive air filter? Makes sense to me! Wait...let me text all my buddies with Roush Mustangs and tell them Jack Roush is a dumbass and remove the air intake for a better performing paper filter. Even the low level Roush packages include an upgraded intake/filter first and foremost. Let's see how quickly they commit me to the insane asylum.
After I installed my Roush filter/intake my AVG MPG moved two tenths (15.4 to 15.6)...not much...but it was enough for me to notice. More than likely the conditioned air increased my volumetric efficiency. More efficiency equals better gas mileage equals more power. After three mods...it bumped to 15.9 (so far). I see answeres on here to questions (like...how can I upgrade my 3.7? Some moron says...buy Ecoboost...yet, my 3.7 runs neck and neck with an Ecoboost after investing just $1600. Tell me again why Ecoboost?) that really don't offer much real world info. But, I digress.. Just saying...don't beat yourself up over it. You wanted the K&N and you got it. Invest in a computer/programmer/monitor and do the tests yourself. See what you get. It's never a bad buy if you wanted it. Factor in other combinations...and it may be your favorite mod.

 

After the Gotts mod, getting a Original 40 Flow SIDO exhaust setup (I know, I know--let the bashing begin lol), and adding a K&N filter, I've noticed a remarkable difference in my lil 4.6. Like said on the previous page--if you want the K&N, go for it. Just study up on how to clean/oil them properly and you'll be good to go.

 

Hey, i have a Borla setup on my 2012 FX2 5.0. However I did have a 40 series SI/DO 2.5" on my 2010 4.6 2v. It did sound really good. Here is a clip:

 

I tried a K&N dropin and noticed absolutely no difference in performance, throttle response, or gas mileage whatsoever. The only thing I did notice was more dust in the intake tube. Tossed it out, cleaned the MAF, and put an Amsoil EaA in and haven't looked back.........