Are the 60S Evo and 60S components interchangeable?

Although the 60S and 60S Evo look virtually identical, there are some key differences.  One of the key differences is the sound systems.  The 60S has sound by Harman/Kardon, and the 60S Evo has sound by BOSE.  This means the sound drivers are completely different for the 60S Evo, and specific to BOSE equipment.  It is possible you may get sound using non-BOSE speakers, but the sound quality may not be optimal due to it.