I am doing the selection of avionics for a new design. One combination I have seen has all of these 3 components: Garmin SL30, SL40 and GMA340. My question is: do we really need all of them? It seems SL30 nav/comm has some overlap with SL40 comm in terms of functions, and GMA340 audio is pretty powerful. Can the combination of SL30 and GMA340 enough to cover and get rid of SL40?