On long highway trips ( + 500 km ) , I need earplugs in my .2 RS
As Dave stated, it is more general noise , like tires and so then exhaust noise that gets you after a while . The car has more of a resonance inside due to less insulation .
I did not need any in my .1 RS
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964 Carrera 4 -- 997.2 C2S , -20mm -- 991.2 GT3 RS