You can perform the work yourself, and keep receipts of the parts installed and that would suffice in the event any fingers were pointed due to some other occurrence....
I've gone through 2 buy backs from dealers / mfgs.
Yes that's true about the rceipt, BUT if and when you have a dealer/manufacturer dispute, it holds a whole lot more weight when you say " I nor did anyone else touch this vehicle BUT the dealer"
With the receipts they can argue ( and they will) that the receipts prove nothing, it does not prove you actually did the work, it only proves you purchased the oil and filters. Yes I know, but that's what lawyers get paid for. Even if you video taped yourself, they would say the video is manipulated and a fake....and they will.
Using the above statement about never touching it has saved me with dealers several times, once I was charged $800.00 for some works on a vehicle, and I disputed it because the problem they charged me for, should have been caught in the previous service - cased closed they sent me the $800.00
So for me saving a couple hundred bucks isn't worth it for the "protection" of the dealer being the only one touching it.
Certainly shop around to different dealers, and play one against the other. Also you can do what I do. I bring in all my own fluids, and filters and say OK go ahead do the change. I've done it with all my diesels Ford, GM, and now Sprinter.
At a Ford dealer I was charged $15.00 for a diesel 7.3 oil change, with all my fluids. They deducted the price of the filter and oil from their standard $29.00 oil change, and charged ONLY the labor part of the $29.00.
AT the Sprinter dealer they didn't have a problem with my filters and etc, but the questioned my Mobil 1 0-40, as recommended by Mercedes saying it wasn't allowed, yea right. When i proved to them it WAS allowed, they did offer to drain there oil out and put mine in , no worries, I'll bring it in next time.
My point is rather than pay their $60.00 for a fuel filter, I get them on the net, and instead of $45.00 oil filters I get them on the net also, and my oil at Walmart.