I can't say I've noticed any odd "drone" noise from the front. Normal wind and road noise - yes; and as it's so quiet these seem more pronounced than in a conventional car. I have the bog standard 19" wheels so maybe it's something that is more pronounced than on your 20" demonstrator. Or, maybe I'm going deaf!
You've also solved a mystery I think. Someone at work swore blind that they'd seen me driving at a time when I wasn't. "But there can't be two Solar Orange i3s hacking around J9 of the M27", we thought. Apparently there were!