Finally got around to remove the engine cover and install the Powerbox for the R320 CDI. You must remove the metal plate that runs the lenth of the engine bay from left to right, there are 2 nuts on each side and one nut in the middle that must be removed before you can get to the rear snaps on the engine cover. Once you remove the metal plate and the engine cover then you can get to the plug to install the Powerbox. The plug is located on the passenger side back towards the firewall I am including some pics of the screws to be removed, the metal plate (after removal), and the engine cover (after removal) for reference. Big notice in power improvements after the Powerbox install. I did a test drive of the car after the install, and as I was turning out from the neighborhood (right turn) I hammered the gas and made the traction control kick in. It felt as though all four tires wanted to break loose. So far I have only driven it around the block so I don't know if there is an improvement in fuel economy yet. I will let you guys know once I get to drive it a little more.

The "metal plate" is normally called a strut brace.

thanks for this tip!

Im thinking of getting my engine steam cleaned, and was thinking about removing the cover so they can do a proper job.

BTW how was the Powerbox