Ooooppps, I didnt know. What should we avoid?
Most of it, from a quick scan through again:
Changing the paint delay will hit your CPU harder so in some cases will actually make the page take
longer to load. If anything, it contradicts the suggestion to turn up content.notify.interval!
Pipelining has a habit of breaking sites, the examples I've seen being online banking (and Fasterfox touches the pipelining settings as well as a load of others and is known as a troublesome extension because of a) the effect the settings it changes have and b) the fact it doesn't remove/revert the settings when you uninstall it). It was proposed to enable pipelining by default, once upon a time, but it turned out to break too much.
I'll bet SpeedyFox, FasterFox and TweakNetwork conflict with each other in weird and wonderful ways - some of them access the same settings too.
Disabling history will break the Smart Location Bar (how else is it supposed to know which sites you visit frequently or most recently?).
Fiddling with things like the download options is not going to make the browser faster really, just hide the "where do you want to save this" box. Likewise for download managers.
Disabling the bfcache will make the browser feel slower (because it'll have to go off and load pages again when you hit the back/forward buttons) for the sake of a few MB of RAM.
Some of the advice is decent, but should be obvious, like restarting the browser occasionally, using as few extensions/themes as you can get away with etc.
