I have a 2004 f250 6.0 liter diesel. I was considering the Flashpaq but wondered if there were any underlying issues with it. Trouble with exhaust or intake. They say with conservative driving your mileage will improve dramatically, is this true or a sales pitch? Then there is the "tow safe mode", what make the other mode unsafe for towing? Will this cause any problems if I just leave the rest of my truck stock? Does the trip computer still read accurately? Thanks for your help on this.

Also I have the same clunking sound as every one else and tried greasing my slip yoke with teflon grease I got from the ford dealer for my '95 f150 that did the same thing. It did not fix it. When some one finds the answer to the mysterious clunk, please share it with us! Thanks.
Kevin