So my C350 has the standard speaker setup. Whilst HK was on my buy list, the car that was available didn't have it and I had read on here from a couple of people that the standard setup was OK. I am not convinced. Indeed I am a little disappointed to say the least. So is there and official upgrade route. I know on the BMW there was an approved Alpine system that could be fitted by the dealer. Not as good as the HK but a lot better than standard. Do MB offer anything similar or am I looking at a complete 3rd party install?