I really like them, having used them, switched to a curved style, hated, it, and switched back. They do have a few caveats though:
1. Expect the mirror segments to be poorly attached. I had one 25 years ago where the panels kept dropping out until I hot-glued them in (or was it silicon seal). Anyhow, bought one recently and as I was removing it from the box, idly thought, I wonder if they ever improved the glue. Nope, one panel fell out right out of the box.
2. In a Locost your mirror will be right at headlight level to the cars behind you, so expect to get blinded at night, especially at lights. I just tip the mirror up as necessary.
3. There's an unsubstantiated rumor that the glass they use is not safety glass, and reportedly shatters into knife-edged shards if it gets hit in an accident. No personal experience though.
4. I'm skeptical of any "auto dimming" coating - best to get that answered via Google.
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Midlana book: Build this mid-engine Locost!,
http://midlana.com/stuff/book/Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from
https://www.lulu.com/