I wouldn't recommend Flowmaster if you want max performance. The best true dual exhaust would consist of:
2.25 inch mandrel bent pipes
Hi-flow cats part# 94106
X-pipe
any muffler that is a straight though design (all magnaflows, bullets, borlas)

ok so would you suggest this or something else?
http://www.youtube.com/watch?v=rpBr3jO8TJM
i want the most performance out of my truck and i have a edge and i will be getting a cold air intake.

I wouldn't recommend a cat-back if your main goal is performance. True duals sound and perform so much better than any cat-back on the market for F150's.

hey man i was going to ask you what you would think i should do to my truck for exhaust i was thinking about roush offroad exhaust. do you have any other suggestion that would be better? for performance and sound i am going to get duals. my truck is a 2006 FX4 5.4 L 3v so what do you suggest for it thanks

will