Proper time to invest in a C55?
I also have a Garmin (nuvi) and I don't think that is any better than the one in the C55 (or even as good for that matter) - FWIW.
But it's still just average sounding at best IMHO. Even the factory premium audio in my Mazda CX-9 (Bose) sounds way better, and I'm not a huge fan of Bose.
I guess my ears were spoiled by my aftermarket sound setup before (Focal Utopia with tube amps and JL W7 sub).




