Is that Pipe Sizing chart for true duals or single in dual out? I have 2004 4.6 2.5 and 2.5 out. Should I go 2.5 in and 2.5 dual out? or should I go 2 or 2.25 dual out? I'm looking for good take off speed and sound.

 

The actual chart lists pipe sizes for both single and dual. The dual is true dual because SIDO won't flow any more than SISO.