I have recently puchased a 2003 F-150 sport with the 4.6L V8 and was wondering what type of dual exhaust would be best?

 

i cut out the muffler and put in a Y pipe (straight pipes) and dual tailpipes and it sounds great! Not too loud at idle/highway speeds, but sounds great when you romp on it!

Next is hi flo cats for me!

 

I don't know about no muffler, but cutting out the OEM Y-pipe would be a good idea. So would an x-pipe regardless of muffler use or not. I would run dual 2.25" pipes on a 4.6L, though.

 

I would consider a name brand cat-back because of quality of materials and workmanship and ease of installation(if you plan to do it yourself). They work well and use stock and stock like hangers. Someone like flowmaster or dynomax makes a great product that will last a long time(aluminized pipe versus muffler shop rust prone pipe) and give you a great sound and you can even get different mufflers depending on how loud you want it to be. Go with stainless tips versus chrome(again, long life, no rust). Good luck, and enjoy hearing that V8 rumble!