Just wondering why bulkheads didn't make it in the top 5? First thing I broke was a set of bulkheads. RPM a-arms, RPM shock tower and body mount, and aluminum bulkheads and poof - dang near bulletproof.
I run the American CNC Machining bulkheads and love them. $62 for front and rear - doesn't take long to get to trhat replacing stock plastic ones.