I'm not sure what you'd call it... I guess its the transmission tunnel interior cover, but its shorter than the one in my car.

Follow up question: if so, where can I get one and would it work with a US spec carpet?

 

It's from an rx7 with backseats, I'm not sure if they made LHD rx7's with backseats though.

 

Hmm, the one in the photo has bins, but I guess it could be a weight saving feature for the RZ

 

They don't have these in USDM cars. These were used to accomodate backseats in the JDM cars but all of the JDM cars had it. I haven't seen one change hands ever. When people install the rear seats in the US they stick to the USDM cover usually.

 

can vouche.
my jdm has bins and the short thingy.