I have for sale an MDF rear parcel shelf for 340 / 360:
It incorporates the original (folding) top part and has black acoustic cloth over the speaker part.
Currently wearing a pair (of quite superb) full range Pioneer 2099 speakers that were fed by Alpine amp before some thieving scum stole it some years back (along with the Infinity free-air type sub that sat in middle of shelf).
In fact the bass from the 2099s was strong enough to interfere with the Infinity sub - I had an inline dimmer switch between the RCA leads to the Mac Audio Amp that fed the Infinity Sub, so that I could fine tune the
amount of bass wallop track to track

(smug)
I still have that dimmer switch that I mounted in middle of electric front window switches, should anyone be interested.
Parcel shelf & speakers needs to go to a good home (an audiofile will definately appreciate) - btw - it slides in and out of the plastic side panel grooves and is a lovely fit.