Ok here's what I have to say.
Yes I have a straight piped 03. Since 03's dont have a cat/resonator it really is straight pipe. It is much louder at WOT then my 2 other 24V were. Under normal crusing and daily driving it is just fine as far as sound goes. I like it and so do my friends since Ive always had straight piped CTD's.
Now as far as WOT throttle... Yes its lound, especially between 2200-2600 rpm at WOT. Its almost like a barking hard hitting noise and yes I like it when I want to show off. Its fun to do under overpasses adn tunnels. I live in a neighborhood and havent had any complaints or problems with the law. I wouldnt reccomend going WOT next to a cop though.
At first I was like "wow I need to get a muffler under this truck" after I left the exhaust shop but now I like it.
Hope this helps
Dan w/ straight piped 03
P. S Its now louder with the smarty