adjusting the idle rpm
 

i read somewhere that u can adjust your idle with a stock stang. (no chip)
its said like a skrew on the throtle body
can U?
if so is it good or bad to do

Why would you want too?

Yes...that works fine. BUT, can lead to problems. You should only adjust it if it is not adjusted correctly in the first place. If the idle is set too low, then the idle will hunt up and down. If it is set too high, it will just run too high.

i was just wondering if it increase performance adn sound quality :)

no just leave it alone, if you have idle problems you got other things wrong.