if u had to choose one ,which would it be?
hi all,i know there have been many threads on horsepower increase in our cars,but i would like to put the question differntly.if u had to choose just one upgrade and supercharger/turbo or time at a racing school/track were not a choice.which 1 would u choose by it self..a. muffler change e.g. fabspeed or the like.b. new headers c. new intake e.g. evo cold air or simialar. d. ecu upgrade .e.g. revo or giac...which of these do u think would do the most by it self..even if its only 5 horsepower.. 
