Bose slight update from later versions
 

Recently I found out that Mazda slightly updated the Bose systems on later versions, so the questions is, I have the 2004 rx8 with Bose audio system, would it be worth to replace front speakers and amp from S2/R3? Or there isn't any differences except visual and locations of amps in front speakers?

It is too different to swap.

Heard that front speakers are straight-swap, all other looks same as S1, not sure about the amp, and head unit are totally different so no plans to touch it :D