Hey two quick questions is V9.3.2 coming to Firefox and will the replay speed improvements also apply to nodisplay !replayspeed?
Yes, later this week 
Yes. The performance tweaks apply to all speed settings, including nodisplay, fast, medium, slow.
Of course, with medium and slow the integrated delays (0.5s and 2s) of these options cover up the performance tweaks. But code wise, all commands use the same new logic now.