The plastic frame is how all these things, a bit thin and fragile. During installation it is recommended to use the DIN mounting frame prior to installation in the vehicle, because it gives additional stability.
The harness with adapter is very straightforward to install, it has the same locking, as before the original BMW radio, thus a sliding apart the plug connection does not exist and you can proceed with the installation carefree.
Watch out !!! Be sure to work with a lot of flair, started already during the removal of the trim on the dashboard!
Somewhat difficult it is when pushing the radio because of thick Kabelwust with the thick plug adapter feel free behind sliding and then the place for the radio is too small. To this end, it could still be required, the lower cladding to reduce the steering column in order to then hold the harness from the side can.
If you have then installed everything and does a soundcheck, you forgot the small Nickeligkeiten again and would be only a functioning radio with great sound and at a much cheaper price than a used BMW radio.
A pity, however, that an accessory radio is not as nice inserts in the dashboard, as before the original, but it was clear from the outset.