Hello Slkers ,i am Dimitris and this year i had spare time to work on my r170.This time i would be upgrading to Bose sound speakers .I bought them back in 2019 and they were waiting all these years in the carton box .I installed all 4 of them but i connected only the front ones to my becker porsche cdr21 4ohm head unit .Oh boy,what a difference in the sound quality .I would say all slkers should upgrade to bose optional speakers.The followong days i will also connect the rear omes and report again .Oh boy,a new slk era begins.