Hard disagree. 8 spaces is waste and 4 should be industry standard. Tabs should not be used for indentation, but spaces. On the other side, Tabs are configurable, so that's actually a plus point.
80 character limit instead of 100.
Why? 80 is an old standard with limitations that do not apply today anymore. We have wider screens and higher resolutions. While it makes sense to keep this to be consistent with previous code and language defaults for C, there is no reason to enforce this for the new adopted language, which already has a standard on its own.
And yes rustfmt can be configured and when I started with Rust I changed max_width to 80, just because I was used to it with Python. But there is no benefit doing this in Rust.