Yep, and I just found out from the local Firestone sevice center that they mark up parts 25%. I saved about $1500 buying my replacement engine myself.
The only problem you might run in to is a lot of mechanics won't install customer-purchased parts. They'll feed you some line about not wanting to be liable for sub-standard parts (even if they are OEM)... whatever... Just find a local garage without that policy and you're good to go.