I own a 06 f150 5.4L great truck but lacking in power want to know if chipping makes a noticeable differents in power before i buy one and install it

a chip will give you 15-35hp. it's not a huge difference, but it's best used in conjuction with other mods. and a quality chip will cost $300-$400.

if you want a ~50-60hp difference, then a chip, new air intake and cat-back exhaust is a good starting combination. it'll give better sound, better intake/exhaust flow and will unleash a bit of extra power.

i have another probem im trying to install factory subwoofer under rear seat has the harness there already but can't get any sound out of it has power and ground but not getting any feed from deck

car audio isn't my area, but we do have a forum for car audio.

http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=675