Just bought a second-hand 2018 T-Roc 1.0. While still getting used to not being in a Passat, I've noticed the somewhat limited Audio capability: Speakers in the front doors, I guess also tweeters in the front, and that's it. Missing sorely sound sources in the rear doors... is that something I can install myself? What should I bear in mind/what are the pitfalls? Can anyone point me to a YouTube tutorial? (I'm suspecting the door linings would have to come off). Or shouldn't I mess with it?