Considering your level of modding ability / desire not to change the truck's visuals, your biggest gains are going to come from modifying the nut behind the wheel.
So you need a "game gauge" for sure, so you can start playing "beat my high score" on your regular commute. Also start logging every fill-up so you have a record & additional motivation.
The SG-e will read & reset codes. The major difference between it and the SG-II is it can't be programmed with custom gauges (which probably doesn't matter one whit to the majority of drivers).
Compare the Features of the ScanGauge products : Linear Logic
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