Mercedes E350 Coupe speaker upgrade advice

[Patrick1964]

I have a 2013 Mercedes C207 with the non Harmon Kardon system and I'd like to upgrade the sepakers in the front of the cabin. Can anyone advise the sizes or a place to source ? I've looked at a few online retailers and they don't seem to list my car, but I can't believe there's nothing that will fit.

Thanks in advance

[Patrick1964]

Just in case anyone is looking for the answer to this problem, the only UK based supplier who know what they are doing when it comes to specifying speaker upgrades for these cars that I could find is https://www.commandonline.co.uk/Sound-upgrades/