This is my solution to the useless storage under the rear parcel shelf. I went through 3 of the plastic rubbish on my +4 in 2 years of ownership and the tray in the Roadster is cracking after a year (less miles). On the +4 I tried a plywood unit with Aluminium Angle at the edges. It was quite heavy and dimensionally I did not get it right. This time I built a patern in Cardboard and had a sheet metal shop fabricate it in 2mm Aluminium. I have lined it with car acoustic foam (yes you could use neoprene). Very pleased with the result and gives much more usable space. I have just had a Roll Bar fitted so there is a removable flange on each side so it gets support at the sides but can be slid in between the Roll Bar support frame.