hey all, im new here to the forum, although iv been reading up on the 6.0 for a month or 2 now. my previous rig was an 02' duramax 2500. iv been a chevy guy all 32 years of my life. i put 189k miles on my chevy with nothing more than a steering box and 8 injectors ever failing. unfortunately (or fortunately, however you look at) the truck was totaled when the ramps on a flatbed tralier failed while unloading a piece of heavy equipment lifting the tires off the ground and dislodging the chock blocks, sending the whole thing, truck trailer and excavator down a hill in to a tree. im not gonna lie, i wanted another duramax but i also realized i had to have a 1 ton crew cab. with the insurance settlement plus a chunk of cash on my part, i wanted to buy a truck outright for the first time. this put me in the 18k range and after months of looking i found zero chevys and only 2 f350's that i would consider. i ended up working out a deal on an '05 f350 cc/lb lariet with every option in the book including a 2in leveling kit and new wheels/tires for $17,500. the truck has 99k of easy high altitude miles. (previous owner was a retired older fella that didnt haul anything more than his dogs) it has rebuilt turbo, installed at 94k and a new tranny/tranny cooler replaced under warrenty at 65k. (apparently it came with or was refitted with wrong tranny cooler, which caused the original tranny to grenade) it's a December '04 build from kentucky and has no MAF. i have all the service and warrenty records and its been regularly maintained and has had no other major issues.
I own a landscape construction company and i do a lot of towing, the trailers weigh 3500k empty and can get up to 13k when loaded down. im pretty up to date on the duramax's and the mods/maintenance that are required to keep the trucks alive under the abuse of hard miles. iv been in the chevy forums for 5 or 6 years.
As for the mods to 6.0l, iv already got rid of the cat, done the zoodad and high idle. iv got an egr delete kit from RCD and a cat back exhaust from magnaflow on order. (had a magnaflow turbo back on my duramax and loved it) so that brings me to a few questions. should i get the STC update kit and do that while i got the motor torn apart for the egr delete? seems the STC failure is not an issue or 'if' but 'when' on these '05's. also iv read it might be a good idea to rebuild the oil cooler... is this necessary in all practical purposes? also, the coolant flush looks like a good idea as well. im not impressed with the factory gauges and from what iv gathered the edge insight with the pyro is the way to go. (had and edge/attitude on the duramax for a long time) im not planning on putting a tune or chip on this truck. im just looking to get the best mpg's, lowest egt's and longest life possible out of this 6.0l motor.
so am i on the right track powerstroke nation? what am i missing? i plan on doing the egr delete and exhaust next weekend, anything else i should be swapping out, or looking for while im in there? STC? it's weird getting reacquainted with a different diesel motor! although im liking what i see so far... i imagine this is what a getting a new girlfriend feels like after your wife left you....

sorry for the long intro, thanks for the input.