The only thing i've replaced so far is the HDD with an SSD. Everything went smoothly during and after the install. I'll be heading to the store this weekend to check out problems with my FireWire port (I think the port is dead). Anyway, I know the HD is user replaceable and even has instructions in the manual, but I'm just wondering if they'll somehow pin the replacement against me and void my warranty. I know swapping out the HD is no big deal, i'm just very careful and anal when inside any laptop that I prefer to not do it unless it's really needed. Any other people have experiences when taking their MBP to the apple store and the tech notices you changed out the HD and/or RAM?