I would get at least that much. Make sure you get the B-Quiet Ultimate, cause its Butyl based, rather than the ashpalt based stuff. Im sure its fine, just dont like the smell, plus the butyl stuff stands up to heat a little better.

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I love the smell of fiberglass in the morning!!

'07 Jeep Grand Cherokee Laredo
-1x MTX 9500 12"
-1x Alpine PDX 1.1000
-1x Pioneer DEH-P7800MP
-100 Sq Ft B-Quiet Ultimate

'00 Civic
-2x Alpine Type X 10"
-1x MTX TA81001
-1x Pioneer DEH-P6800MP
-100 Sq Ft B-Quiet Ultimate