Join Date: Apr 2017
Location: Western Pennsylvania
You might try using dynomat. It has sound deadening characteristics. Not cheap. Just cut it and it sticks to whereever you put it.
That's what I am using in several places on the car. You can see some under th edrivers seat (installed by the PO) in the images a th ebeginning of this thread. I'm also goin got add it in the rear in an effort to close up the gaps that are commonly seen between the rubber mats and vinyl drapes.
Alfa-current: '66 Duetto, '69 Spider
Past: '74 Spider, '76 spider, '80 GTV 6
Other-Current: 11 BMWs, Ram 1500
Other-past: 16 BMWs, MGs, Triumphs, other stuff that doesn't count.