2003 exhaust

hey all got a 03 with 5.4, wanna make here sound good. i'd like dual exhaust with the pipes comin out behind each tire, looks like theres room. i figure for now just straight pipe from the cats back. has anyone done this? wondered if it would make it throw a code or it would be ok. found tons of vids on youtube with dual exhaust and pipes but wanted to make sure it wont mess with the computer.