Have to agree with Vegas on this. It is not just an oil change for 5000 miles and if the dealer did the proper 5000 mile service, the money they charged seems reasonable. If they did just an oil and filter change, then find a better dealer.
It is also good to learn to wrench yourself. As far as warranty goes, can not find anywhere in the warranty section that says if one does not have service done by BD Dealer or authorized service center, that warranty will voided.
If an owner does their own work and does it using the proper parts, tools and equipment and has the skills and knowledge to do so, warranty should still be valid. If owner has work and does use the proper parts, tools and has no idea of what they are doing, well why should BD cover such if Joe Blow screws up something?
Now if there is an item that does need to be fixed under warranty, then that does have to be done by an Authorized Service Center or BD Dealer. Key is authorized and there is times when the owner, working through BD or any manufacture can get the authorization themselves.
As far as S & S goes, they recommend the Mobil 1, however it is not required! Big difference. Per the S&S Web Site Tech Tips for "What Type of Oil Should I use.
"What type of oil should I use?
S & S recommends a premium brand of 20W50 oil formulated specifically for motorcycle use for all Long Blocks. In Shovel-Style Long Blocks, 50 or even 60 wt oil is usually acceptable in hot areas where temperatures below 75� are seldom encountered. In S & S's experience it is best to break the engine in with petroleum-based oil and, if a synthetic oil is preferred, change to synthetic after break-in."
Mobil 1 V-Twin 20W50 is one that meets the above along with a few others. If you stick in say Quaker State 4X4 Synthetic blend and have an failure due to oil, that may not be covered for it is not a premium brand of 20W50 oil formulated specifically for motorcycles.
Last note, if you do have a warrany item and did work yourself, for the most part they have to show what you did directly or indirectly lead to failure such as wrong oil and you have a failure due to oil, changing a light bulb to PIAA and having and oil failure is not directly or indirectly realted. Failure to follow break in and proper service is a reason in most case for the typical service intervals cover checking almost everything from change of oil to make sure all bolts are tighten, adjustment made, wearable items inspected, fuel filter cleaned, etc.
Also since you did not take yous in for the 500 or 2500 miles, some of those items done on the 5000 should have included the items that were not doen for the 500 and 2500 and not included in the 5000 mile.