Simple Rated 4 out of 5 stars
Hard to say if it makes much of a difference in the real world.
I should add that FF8 reduced the max connections to 48 (from 256 in FF7) due to a bug that was net yet repaired. Also, as of FF3, max-connections-per-server defaults to 15. The Mozillazine Wiki says that persistent connections above 10 are considered excessive.
Rated 4 out of 5 stars
Basic, simple ways to make changes without going through about:config.
If you have issues with pages no loading, try disabling the pipelining options. Some sites don't work properly with it enabled.