I owned a 2018 SXT and now I own a 2019 GT.
Differences are:
- Leather/vinyl seats (GT) vs. cloth (faux suede)/vinyl seats (SXT)
- Navigation system (GT)
- LED interior lights with more, separately switchable lamps (GT) vs. incandescent dome lights that can't be switched on individually (SXT) (someone reading in the back would have th driver blinded by the front light also having to be on)
- Inside roof console with multiple fold-down compartments (probably optionally fold-down DVD screens?), with a blue "halo light" (dimmable) all arouoond it (GT) vs. "plain roof" (SXT)
- Instrument cluster info display has WAY more data and features/pages/modes on GT (on SXT, I coul;d never see the trip counter and odometer at the same time, GT has multiple items visible concurrently with more informative (text-based) warnings/data
- Heated steering wheel and front seats (GT only)
- Automatic climate control (GT) vs "regular A/C" (SXT)
- Sound system has more spakers in GT, with better bass
- Switchable 120V inverter in GT
- Blackened headlight and front grille trim, as mentioned before
- Black painted alloy wheels (GT) vs silver painted (SXT) (wheel patterns/shapes seem different)
- Retractable sun shades for middle row windows
Everything else seems the same, EXCEPT my GT doesn't have a factory roof rack, which is a pity... (I'm contemplating installing one as they are handy)
Hope this helps, and good luck.