Disagree. Readability is not about 4 or 2 spaces, it is about strongly enforced convention that makes these typographic details literally disappear from the eyes of the readers. This effect is very noticeable in book publishing: if you ever notice the typography, the typographer failed at his task. It is the same in code, just file the rules and it will become your preferred guideline in no time.

And repeated experiences everywhere point to the fact that code text is already very hard to manage, very sensitive to alterations, misreading, etc. I'd rather remove layers and tools than add more.

Edit: obviously, readability is ask about convention when they are within the realm of sane acceptable conventions. And by everywhere I mean in teams where the loc count is above a few thousands.