Here you go, I imagine some of these are underhand pitches for the HN crowd, but here you go. There's a few that most users are simply unaware of, such as replacing the Airport card with one that supports ant continuity and handoff and Airdrop support.
7.5 years later, and my 2008 Mac Pro is still going strong.
http://blog.greggant.com/post/58331227038/recommended-mac-pr...