I've never trusted stealerships. I bought my current car, used, through a fairly large Ford dealership. They slapped an inspection sticker on it, after i told them specifically not to. I wanted to go to my inspection guy, because he's thorough. The car ended up needing a tie rod. I had to fight with them for over a week to get it fixed. I ended up going there Saturday morning walking around the lot telling people my story until a sales guy overheard me. The owners son came out, apologized, and had my car fixed right there. I probably drove 50+ people away that morning.
Have the dealer do it to get the new parts, go home and take it apart and redo it to make sure it's right.