I don’t have information about StallGuard, but based on posts on this forum, I don’t think it will have much impact. The two changes that appear to have the most impact in speed area are:
- the speed of the processor on the control board
- the voltage used to run the steppers
The most extreme example of performance improvements I’ve see are Steve M Potter’s build detailed here.
I also see at least one posts that a typical MPCNC build using an SKR Pro board running at 24V which had substantial performance improvements over the 8-bit boards like Arduino Mega boards running at 12V.