My Avuras were crystal clef, my Infinit and my friend's Infinitis all sound like you were in. Muffled tunnel. The A6 sounds very clear, most people say I do of sound like I was on BT.
2014 A6 Prestige
Ice Silver on Black w/ Driver Assist, Full LED, Black headliner
3M Crystalline 40% Tint all around, Akebono Euro Ceramic brakes
Hartmann HS5-209-GA:M wheels and Michelin Pilot Sport A/S 3 tires
Most recent rides:
2011 Infiniti M37 Sport, 2009 Acura TL SH-AWD Tech
2008 Acura TL Type-S (#2), 2008 Acura TL Type-S (#1), 2007 Acura TL Tech
2007 Camry Hybrid (don't ask)
2006 Acura TL Tech, 2004 Acura TL
2002 Infiniti I35, 2000 Infiniti I30
and over a dozen more before these.