Do you void the warranty on a 2006 SuperCrew 5.4L by making it true-dual??

Thanks and I appreciate all the help I've been given on this site the last couple days.

 

Depends on your definition of "true duals" I suppose. No cats to straight pipes I am sure would void the deal. I once leased a 2001 Ranger with the SOHC 4.0 Liter and was told by the dealer anything after the catalytic converters was fine. The only way I finally got the damn engine loud enough to hear idle was to replace the muffler with a piece of pipe. Oddly enough, when I went to turn the truck back in two years later I was told I had to put a muffler back on it or pay a fee. Fortunately for me I had kept the old muffler and the only expense was a little time and trouble. Your experience may vary, but whatever the Ford dealer tells you, assuming you ask, get it in writing!

Good Luck!