This whole platform makes me nervous, every noise and vibration takes a week off my life and a chunk out of my account. somehow I still find it worth it, the dealer that did my chains and pump had an invoice of around 5k give or take, included plugs and some other routine maintenance items, but that was a Ford dealer so I expect it to be kind of high. I would highly recommend an oil pump while you or the mechanic is in there, it is worth the preventative maintenance and a Melling high volume is under $200, and once the water pump is out of the way it is literally right there behind it, the procedure to replace the oil pump is the exact same thing as the water pump. I'd say plan on 5k to have a shop do it, could be less, but to do it yourself if you have the ability (know your limits, this is a deep job) you could probably come out around $1000-$1500? Maybe even less, its a matter of parts quality and what all you decide to replace along the way.