I had a 05 F350 with the 6.0l for 2.5 yrs. I added the coolant by-pass filter. Never opened the filters, just swapped them. Make sure you look at doing a full flush on the 6.0l and switch to a better recommened EL (extended life) coolant. Suppose to be better for the 6.0l compared to the Ford coolant at the dealership. I also ran the oil by-pass filter system as well. After my 3rd by-pass filter, I extended my mileage interval by almost double. I had the FS2500 from my locale (http://fs2500.com/product.html). I just recently sold it (removed it prior to trading the truck in for a hemi mega).
I was presented with website http://www.dieseloilbypasskits.com/ for price comparison. I opted for the steel lines and the return line to the valve cover. Check them out.
I had to add the EGR delete kit as it broke on me 2 states south. When that was completed, I added custom tunes via the SCT tuner, didn't go big and heavy. Lastly, I removed the cat for a straight pipe and bigger downpipe. I was hoping all this would provide a better operating fuel efficient deisel. But nope. 12-13 around, 9 towing. My hemi gets 13-15 around and 10 towing with no upgrades.