advantage by compiling kde on your own pc....?!

[AndiX33 at aol.com]

hello, 

michael mcconnell wrote:
> When using
>  KDevelop, i'd recommend that you install both KDE and QT from a source 
> package, compile it, and install it yourself. This will
>  result in both better preformance, and it will make them work >with more 
programs, 

what improvement can  i  expect when compiling kde from the source. i did it, 
but just for fun.
can you express it in real numbers how much faster programs will run then? 
and what do you mean writing "...it will make them work with more programs". 

greetings 
andreas schmitzer

ps: having compiled all from the source and  then writing "make clean" 
doesn´t really delete the folder with my extracted source-packages. can i 
delete the - now useless- source-folder or do i harm my system then?