I'm thinking about putting a new custom exhaust under my truck. I was hoping to see what you guys think is nicer/better and give me more power/fuel economy. The truck is a 99 5.4. Tell me what y'all think. Both of them would be exiting out just in front of the rear tires.

 

checkout the underside of your truck. you have to route it around the tank, frame, etc.

 

The x pipe will give you the best performance also Borlas or Maggie's will give you a decent boost in fuel mileage. I would recommend ditching the catelytics that will give you a nice gain as well.

 

X pipes are for hp gains in big power making motors. Don't do much here. H pipes are more for torque and better suited for this situation.
Granted with our trucks a catback doesn't do jack squat so x vs h debate is kinda pointless

 

I was think about starting at the motor and getting headers and throw away the manifolds because they rattle. Then I was debating on leaving the cats or taking them off, it sounds like Some guys are throwing codes because they cut the cats out and I don't want that to happen even though I live in Iowa and we don't do emissions test or anything of that nature. I was leaning towards going with the H pipe kit off of jegs.com and for the mufflers I was going to put on the flowmaster 40 delta flow muffler.

 

Ok

 

Stop by a couple local small shop and get a quote for what you want. They may be able to beat the prices of some clamp on kits.

 

Cut the cats and do the Gotts o2 mod and you won't throw a code.