when i got my Z'd the back seat was loose, on closer inspection it looked like there was 2 retaining clips at the front which had popped-out. When i tried to get them back in they just popped-out again. I ended up taking the targa roofs out and jumping up and down on the front edge of the seat but only one is holing. I gues they're worn but can't understand how, it's not as if the seats are in and out all the time. I did notice a small'ish box in each seat well under the seat with wires coming out of them, they didn't look stock and i thought that these were perhaps preventing the seat from droping down enough.

 

Anyone know what these boxes might be?

I never noticed any boxes in my seat wells when I replaced my back seat - possibly right in saying that they are not stock.

Possibly small amps for speakers?

The amps for the rear speakers on mine were inside a housing which also held the rear speakers.

Possible yours have been moved, but as to why, dunno.

Even with the boxes, they would have to be a fair size to stop the seat "seating" properly.

Methinks the clip worn/broke.

Stupid-clutch at straws question - I take it your seatbelts are out the way?