I was just wondering, would it be beneficial for me to compile the programs on my system that i use most often (mozilla, open office etc) as well as gnome? Would i notice any sort of significant increase in performance?? And if i were to do that here are a couple questions:

-If i compiled a program, mozilla for example, would it overwrite the original? Or would i have to make a new link between the command 'mozilla' and the new executable.
-Will there be a significant increase in performance?
-What file do i edit to choose optimizations for compiling?
-I've heard that doing 'make install' can be a bad thing? (i'm using arch linux right now) Is this fact or fiction? And if it is fact, what do i do instead?

Thanks for any help!

Compiling a program specifically for your machine arch will improve performance (all be it very slightly) you may get 0.5 less load up time, not really worth it. It would also be better to remove old miozilla first.

when running ./configure if you hit ./configure --help it will give any optional flags to compile it with.

make install is generally the way to copy the binaries into their set locations either by default or where you specifiy with ./configure --PREFIX=<location> there are no problems with make install being dangerous that i have EVER heard of. well maybe with compiling a kernel, but thats a bit different