Firstly, Buffy/Angel sex did not cause disruptions around the world. That, like most of the insanity in the Whedon-verse, is caused by the higher ups; deities and whatnot. "Destiny sex" was putting it mildly.
Do you have anything that actually supports that? Actual evidence?
Nonetheless, they still destroyed mountains whilst having sex and crashing into them so their durability/destructive ability should be around that level.
As for outrunning a bullet, not that impressive. That's low-supersonic.
Buffy has better feats.
Buffy flew from Tibet to at least Budapest, England and Brussels before two people right next to her noticed she was gone and then came back before Dawn could finish two words. This is at least 11,000 km covered in a couple of seconds.
Using Dawn's incomplete sentence as the time-frame and it would be around a second or two.
11,000 km/s is Mach 32,039.4, that's what it was if it was 1 second.
5,500 km/s is Mach 16,019.7, that's what it was if it was 2 seconds.
3666.6 km/s is Mach 10,679.8, that's what it was if it was 3 seconds.
That is hilariously faster than anything in Bleach.
In terms of travel speed, Buffy takes that since Bleach was never about travel anyway. As far as Combat speed goes though, Ichigo outclasses her completely.
No. I heard enough of that nonsense on the internet.
A character that travels that fast must have the reflexes/reactions necessary to keep up with themselves to effectively travel to where they want to. Otherwise they would have little-to-no control of their movement. There are instances where a character has superior arm movement/attack speed when compared to their movement speed (Cars from JJBA for instance) but a movement speed feat should also correlate towards a character's combat speed.