I kept rear speakers in my 500E as I often have rear seat passengers. So, I cut the hole that JCE proposed and it works just fine.

I too was concerned about road noise coming through, so I Dynamatted the entire trunk. It's as quiet as can be now; Dynamat's good stuff.

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"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo