Guys, I'd like to do some things to increase the fuel mileage and power (a little...got the 48RE) in my '06 CTD, but I don't want the dealership to have any reasons to void my warranty.

Here's my plan so far:
Install Amsoil's new dry resuseable air filter in the stock box
Consider the Rokktech sensor
Consider Rokktech's muffler after talking to dealer to see if they squeal
Switch to all synthetic fluids after about 50,000 miles

Any suggestions or comments?

Has anyone done any scientific testing to guage the benefits of each mod separately?

You won't see much difference from those mods. Keeping your foot out of it will net you the best result. You could swap a AFE pro gaurd into the stock box. Make sure your tires are inflated. Do a search on warranty info and you will see that most guys will tell you the warranty depends on the dealer. Some will void for electronic goodies others won't. Hope this helps.

RIPOIL, if you want efficiency, the Rokktech sensor will definately help, you will feel the timing advance also. I am in the same boat as you, I want a little more snort and economy but don't want to mess with warr. either. I assure you if you buy the sensor you will not be sorry. I got around 1.5 mpg from mine and more power off the line and in the midrange. I am also going to get the muffler from them.:cool: If you need any more info on good mods PM me.[tapdshut]

get a box and take it off before going to the dealer, just play stupid...

Fuel additives help.. I use Stanadyne and it gave me 1+ mpg.. and it helps other stuff too...

Any problems with the timing sensor as far as getting things too hot??? I just ordered one but will not be running any guages, just looking for a little increase in fuel efficiency.

Will these void the warranty? Will they even be able to detect it? Thanks