The rear speaker grills simply lift up and unclip. Be careful though as they need to lift up from the front as they are hooked in at the rear. Just go slow and steady and you will be fine.
When I began planning this install I originally decided not to upgrade the rear speakers and was going to leave them stock. Had I realised this would not be the case I would have ordered an additional two speaker connectors from Technic to keep them plug and play.
To get around this oversight I ordered the following parts from BMW (after Technic kindly provided me the part numbers!) and I made up my own connectors for the rear. If you are ordering Technic’s harness I would recommend his speaker connectors as his speaker wire is a thicker gauge than on these parts and much less hassle!
Part No. 61138373583 x 2 – These connect to the cars plugs.
Part No. 61130005198 x 4 – These fit inside the above plugs and are secured by a push down clip.
Here is my connector. I used the speaker wire supplied with the Vibe Slick 4’s, cut to length, and soldered them onto the above connectors wires before heat shrinking. Not the best picture but plug and play and secure.
The Vibe speakers have four mounting tabs whereas BMW’s fitment requires only three. The tabs on the Vibe speakers are made in such a way that they can be cut off by carefully snipping them with wire cutters. Any remaining rough edge can be filed down easily with a file before mounting. The speakers fit fine and all I used was the original fitting screws but added a washer around the top screw to allow it to hold the uppermost edge of the speaker in place.
Again after fitting I tested the rear speakers worked before moving on.