There have been a few threads on hear discussing the rear tonneau cover.
I have an '09 Base model which didn't even come with the holes/hardware to install the cover. I was originally planning on cutting my panels and adding the hardware, but I found a serious deal on all of the panels from a race part-out.
In the process of installing the panels that had the correct holes/hardware, I discovered that the only difference between the panels that I had and the panels that come with the holes are the cut-outs and the hardware. The panels have outlines for cutting the correct holes. Instead of spending beau coup bucks on replacing the panels, you can spend about $90 and do the work yourself. Of course you still have to buy the tonneau cover, but I wanted to make a thread showing how to cut the panels and what hardware is needed. There are plenty of threads showing how to remove all of the rear panels, etc.
Below is the rear speaker panel. The first photo is for reference for the position of the cutout. The second is the actual outline that has to be cut out.
These are photos of the panel at the bottom of the rear decklid:
You will need four of the standard 10mm head bolts used all over the car. If you don't have any extra, I used M6-1.0 from Autozone. These are used to secure the hooks on the decklid and the mounts on the speaker panels.
This is the list of parts from Courtesyparts.com that are needed for the upgrade.
You'll need six of the screws for connecting the "Bracket" to the "Mask".
Rear decklid:
909 Back Door Trimming :: Body(Back Door & Rear Body) :: Genuine Nissan Parts :: 370Z Parts (Z34) 2009-2010 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com
Speaker panel:
769 Body Side Trimming :: Body(Side & Rear) :: Genuine Nissan Parts :: 370Z Parts (Z34) 2009-2010 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com
Once you cut the slugs out of your panels, then it's just a matter of putting the "Bracket" (back side of panel) and "Mask" (visible side) together. The hooks just pop into the holes on the rear deck panel. Make sure and use the bolts to secure the pieces to the body/rear deck lid. It will be quite obvious where the bolts go once you pull the panels off.
Below are two photos of the final installation. (Thanks to member G Fo12ce. I nabbed his pics.)
If anyone needs any clarification, let me know and I'll be glad to help. Doing this can save you 2-300 dollars in panel replacement.