Hi Folks, I have an '08 GT/CS and would like to start on some horse power upgrades. I don't want to void any warrenty so does this mean all items need to be Ford Racing brand and also does this mean I need to have FoMoCo install the upgrades?

Also where would you start? What would you upgrade 1st, 2nd and so on? As far as exhaust goes I am willing to change but do not want anything thats really loud. I still want that famous Mustang GT sound. Any help would be great. Thanks in advance!!