I don't think anyone has enough miles on one of these to have changed the plugs yet, so you might not get a response to that. And yes you do have to pull the cab of on the 6.4 for quite a few different things...totally rediculous and that's one of the reasons I'm trading mine in next week for a 6.2. Along with the fact that diesel is more money, without any gain in mileage. Also the higher maintenance costs of fuel filters, oil etc. And don't get me started on that f-ing "regen"....what a horrible idea. I looked under the hood of a new SD w/6.2 when I test drove it and there is alot more room under the hood than there is with our 6.4's. You won't see any cab off repairs on the new gas trucks. Being such a new engine, it may take awhile yet to prove itself completely, but so far I haven't heard any major horror stories.