its the buyer's responsibiilty to develop a relationship with the dealer service manager and understand that this guy has a fair amount of authority and has been authorized by DC to exercise good judgement in cases of warranty questions. Some dealers take a hard nosed, 100% "legalistic" and verbatim interpretation of the warranty -- perhaps because a few customers have driven them to it. These are the dealers who refuse to work on your truck if you have so much as a fuel pressure gauge hooked up to your VP44, for example.
Other dealers, depending on how you treat them, are quite reasonable. they understand the MM warrany act, the durability of these engines, and use good sense. These are the guys who know that a mild performance box is probably not the cause of throwing a rod, and would approach the warranty question with some good sense. Some such dealers will warrant your front end even when you put on 285/70 tires, when DC says only 265. Some of them install after market exhaust and understand what it means for an after market part to cause something else to fail.
The difference between these two types of dealers is often the customer. If you barge in and demand an entitlement, you will probably get treated legalistically and the manual/warranty statements will probably get interpreted verbatim. the Dealer will probably escalate up to the Zone rep and so on, and guess what: the more you demand entitled warranty covereage, the more you will attract "by the book" attention.
Its those gray areas of the warranty that you want your dealer behind you. Cause if you throw a fit, all those gray areas will probably turn black real quick.
I think people largely mis-understand what the dealer's job is. not only do some folks believe that the dealer is the mfg; they believe that because the dealer made a $200 profit or barely broke even on the new vehicle, that they are entitled to luxury loaner cars, compensation for vehicle down time, and general red carpet treatment.
My 02 2500 was a pig, and I was always into the dealer since the day I bought it. I found, however, that by being patient with the dealer, appealing to reasonable action instead of demanding entitlement, I got very favorable response and a willingness to help me out. thats where lots of folks don't get it: the dealer is your advocate to the zone rep. He can speak volumes for you, how valuable you are as a customer, how you should be treated, how you treat your vehicle, etc. do you want that guy on your side or against you? When you're in a gray area of the warranty and it isn't clear whether or not your mod caused a failure or not, you're gonna want the dealer on your side, not suspicous of you. otherwise, the official answer will always be "no warranty coverage". In extreeme cases they can slap a limited warranty onto your truck, which is a perminent designation, not just a one-time refusal to cover a certain repair.
so back to fueling boxes. My dealer told me he would stick up for me even if I put on a mild fueling box on my 02 (the EZ). Since I actually put on a comp box in EZ mode instead of the EZ itself, (didn't hook up the VP44 pump wire) I took my box off when it went into the dealer. no deception at all, but at the same time I didn't want a mechanic going balistic over nothing and calling un-due attention to this mystery box that they didn't know about. Thankfully I never had the chance to test the dealer to this level, but I'm confident that if my 02 had thrown a rod, they would have covered it.
now then, you put on a hot box like the new Edge, that does timing, duration AND pressure, you are pretty much outside the envelope in my opinion and have no business asking for warranty coverage for the drivetrain. Tweaking up the engine with mild power mods until its output matches what the same block normally puts out in commercial duty is reasonable. but putting on a competition box that pushes the engine well beyond any power lever used commercially is outside of that gray area in my opinion.
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