BTW, I have a similar product that OP asked about currently on my 2017 Ram 5500 set to 60HP/120TQ. I really do feel it, and I reason that if my mileage DOESN'T drop while using that extra power, it's a mileage improvement, otherwise there would be a mileage drop using more power.
I bought my module in 2018 and like it. Feel it on the bottom and middle, where I typically run this truck.
I dont post about much cuz there's a bunch on here who don't believe in modules. Smarty was a great product, but had issues with the Italians getting back with me, then reading through their website.found they didnt support 4500/5500 trucks. Then someone pointed out where one location on their website said they do and another area said they didnt.
I got the power I want for $500, and with Smarty, the programmer, the unlock, and other mess was somewhere around $1200 to $1500.
Anyhoo, That the WHOLE story.
Cheers, Ron