A few weeks ago, BMW began letting a few select journos into its super secret CSL garage, filled with incredibly special prototype cars that never reached production. The four cars BMW decided to show off were the E46 M3 CSL V8, the M2 CSL, the E60 M5 CSL, and the E63 M6 CSL. In this new video from Top Gear, we get to see the latter two up close and personal, like never before.

Admittedly, we actually spoke about the M5 CSL and M6 CSL in articles of our own. However, we weren’t given access to the garage, like Top Gear’s Ollie Marriage was. Which is why this video is so fascinating because it shows off details that we didn’t already know about. For instance, the E60 M5 CSL actually had an air vent where the license plate used to be. Inside the license plate bracket is an air vent grate, allowing the M5’s V10 to suck in additional cold air. The E46 M3 CSL has an extra, asymmetrical air intake but the M5 CSL’s is far better integrated. Very cool stuff.

In the M6 CSL, you get to see the extend of BMW’s interior weight savings. Despite the M6 being a comfy GT car, BMW decided to completely strip the interior out to make it lighter. So it got lightweight door panels and a completely barren center console. Admittedly, BMW kept the very heavy standard seats but they would have almost certainly been replaced if the car went into production. The M6 CSL would have also been first M car in history to use active aero, thanks to its active front splitter and rear wing.

Both cars are interesting pieces of BMW history and are fantastic to see up close, as you do in this video. The only shame is that BMW never actually made them, as both would have been very cool cars back in their day.