Previous discussion linked below, for background. @Edgeman

After plugging in the unit to my OBDC, the difference in performance is pretty profound. Having all 8 cylinders engaged at all times is WAY preferable to whatever the heck the DFM (Dynamic Fuel Management) programming was doing. The throttle response is much better, power delivery is stronger, smoother and more consistent, and the exhaust growls all the time, not just under heavy throttle.

To be fair, it's not much of a growl. An aftermarket dual exhaust system is next. In reading reviews of the DFM Disabler (from Range Technologies), users were talking about how their aftermarket exhaust systems "droned" whenever the engine throttled back to a lower number of cylinders (which is, like, all the time). Once they installed the DFM Disabler, the drone went away, and the exhaust sounded great. 👍

Having experienced the truck with the DFM turned off, it makes me sad for the 10,000 miles I drove it without the disabler. Not only does this device make driving more enjoyable, but it will help the engine last much longer. DFM's predecessor, AFM (Active Fuel Management) was causing lifters to get stuck, wreaking havoc on engines and causing massive failures and repair bills -- mostly in older engines, around 120k-130k, but still...

The only reason I give it an "A" instead of an "A+" is because it looks like it's taking a 1 MPG - 2 MPG chunk out of my gas mileage. I got 17.8 MPG the first 10,000 miles, and it looks like the next 10k will be in the 16.0 - 16.5 range.

Totally worth it, especially when you consider that my engine will be much less likely to fail and cause a $4,000 repair somewhere down the line.

I totally recommend this upgrade to owners of V8 GM vehicles. I can't believe there are millions upon millions of cars and trucks driving around with this destructive DFM crap installed and active.