Make your Firefox trim and as you want
*www.techtree.com/India/Guides/The_Fox_Slimming_Regime/551-85701-584.html
I'm sure people here can search links.. moved away from tutorials.
Yes we can configure Firefox by many Add-ons. But we must also look that these Add-ons must not have Security Risk of Hijacking your PC. We must take extra care before going to configure it. I think this is what IE have done for the best. Of not allowing a third party Add-ons for IE.