In advance of the Euro Tour last year and while replacing the soft top and sliding head of the RP I fitted quite a lot of sound deadening to try and reduce the noise levels experienced.
The attached photos show the bitumen backed 1/2" felt I fitted to the roof and sides of the body. I bought a roll of the sound absorbing?/deadening material which has a sticky back and a diamond shape impressed on the outer surface, it is quite heavy, easy to cut and sticks like ..... to a blanket. I fitted new rubber floor covering over the sound deadening. I also fitted it in the under seat boxes, below the back seat and up the bulkhead.
I think the single biggest difference has been the gearbox cover. In the past I have draped several layers of towel or foam backed with thin rubber over the gearbox and noted the improvement. The new cover is made from aluminium, lined with the sticky sound deadening and ribbed rubber over to match the floor covering.
Did we notice much difference? Well it is possible to have a conversation inside the car now, at least if the engine is switched off, otherwise the usual shouting match is the order of the day. Actually we did notice in 3,500 miles being rather less worn at the end of each day, which might be due to reduced decibels. Whatever, I felt better about the car and it is noticeably warmer in very cold weather.
The gearbox cover, which is fixed to the floor with two screws and must be lifted to access the filler plug, must modify with a swing plate
Felt lining to the roof and sides and a piece of carpet behind the rear seat back, which also protects the body when the seat is removed to carry luggage for longer trips
The passenger side of the gearbox cover, note oil creep!
The sticky diamond shape sound deadening, also covers the bulkhead. Note the large grommet fitted to the bulkhead to aid rear core plug replacement and the 240 volt 13 amp inverter is for charging batteries and lap top. I am using a military engine crankcase which is 1.5" longer than standard, so the speedo drive has been rotated 180 degrees to miss the rear cross member.
Floor, under seat tool box and former battery box all treated to sound deadening