i went from a 99 to a 2014, wouldnt hesatate to do it again. i had my 99 hoppes up to 925 ftlb of torque and my 14 with only 800 towas my 5th way better and gets simular milage. I know a ton of people with 11+ f350 diesels (probably about 30) no one has had any real problems, the worst I have had is the heater for the DEF tank (cost me 300 to fix as I am out of warenty) I have heard stories of the frel pump granading but never ever heard from any one who has had it happen but since s&s makes a kit to protect against it there must be a market for it. seams like a cheep bit of insurane so I am looking at doing that eventualy.
My 99 7.3 was a great truck and I had some fun with it, but the 6.7 is the first one since that I have no hessitation in upgrading to it or recomending the upgrade.
Steve
