Yeah, I don't trust dealerships. You never know what cheap oil they're using, or if they even bothered to change your filter.
I change my own, and I always keep extra oil ready. Pennzoil Ultra Platinum, nothing but the best.
And with our twin turbo setup, we should be checking our oil levels periodically between oil changes. Adding oil whenever it gets low on the measuring area. Forced induction motors tend to eat oil.