Electric Vehicle Forums - Should I be using Premium?

Should? Negative.

Could? Yes, but any improvements is so small you won't "feel" it. The slight (5-10 claimed) increase in horsepower may show up on a dyno graph, but even the most sensitive rear ends won't feel it in the seat. Still, others will claim that they can feel the 2-4% increase of 255 HP.

Synthetic gas? Synthetic *oil*, sure. Especially if you use extended change intervals. But really, it's all a matter of opinion. You'll see a lot of claims of people driving 300K+ miles and swearing the lack of engine problems was the result of using synthetic oil. Then you'll have those that do 300K+ miles on regular oil and have the same results. Like I said, it's a matter of preference. I used both regular Honda oil and Mobil 1 synthetics every 5K miles and sold my car at 95K miles without any issues. However, it's a Honda. I'd expect that even if I used $1/quart oil from the Dollar Tree.

Just for though, I worked for a transportation company that had several very high mileage vehicles that used the cheapest oil that the boss could buy. Sometimes the change intervals went as long as every 30K miles. Seriously! Not a single one of those cars ever had an engine problem. And most of them had over 500K miles. Two in particular had over 700K miles when I left the company. I'm sure they acquired a lot more miles before they were finally retired due to other issues, not engine related.