To put the cost of premium in perspective a little:

If you get 16mpg and use today's gas prices (just checked costco) regular is $2.35 premium is $2.47.

100k miles on regular at 16mpg costs 14687.50
100k miles on premium at 16mpg cost 16562.5
The difference in cost over 100,000 miles is $1875

At 20mpg the cost difference is $1,500.

The difference in price from premium vs regular is pretty low relative to the cost of a supercharger. On an annual basis of 15,000 miles it would be about $280 per year.

The supercharger design has internal bypass ability so when not under load - cruising - it will take less than 1hp to spin assuming it's comparable to their other superchargers. Combined with less shifting can actually improve overall mileage if you drive it similarly. That's probably why the TRD supercharged tundra in some tests gets better mpg than the non-supercharger version.

It really depends on where you live. Up here Premium is $0.60 to $0.70 per gallon or more than regular.

At that price you're looking at $4000+ more per 100K miles.

Edit - To clarify, no one is buying a S/C for efficiency and everything has a cost associated with it, but getting less than 20 MPG with premium hurts.

MPG is something I chase knowing it's probably not worth my effort. My daily commute is only 5 miles.

I buy cheap gas myself. But I did buy a 2nd set of street tires. On two back to back road trips I averaged 16.5mpg uncorrected with my 285/70/17 all terrain tires P rated -- and the next trip on 50% of the same highway - just a shorter out and back, I averaged about 18.9 mpg with 275/60/20 tires uncorrected - highway tires. And the 20's are actually taller at 33.1" vs 32.6". The first trip was a combined 1300 miles. Second was 650 or so. So not a ton of miles to make an assessment, but I've found roughly that relationship in other driving as well.

Also I don't bolt anything unnecessary to my 4runner. No roof basket. No light bars. I don't leave a RTT on for daily driving. That sort of thing. I keep the OEM rake. I'm sure having a RTT that gets left on has more impact on cost/mile than premium fuel.

My biggest challenge is towing my camper. 14mpg. And that's if I keep it around 70mph. At 85 I'm down to around 12. I would love to see if a supercharger would improve that figure. I kinda think it would. But so would a Tundra. So... hmmm...

Any update on this thread?

Just picked up a 2018 TRD Off Road w/ KDSS. Noticed that that older TRD mods (intake, supercharger) aren't options (yet?) for my model year. Also, the TRD skid plate won't fit without mods due to KDSS. Is TRD fading away?

TRD is now more into stickers, badges, and bling cuz that sells..

Their supercharger program died a while back.. should be happy they still have a few performance mods left in the catalogue.

Ingenuity and aftermarket is where you need to be looking for real mods