Dynaudio is the upgrade stereo system for some models of the Golf, not available on the R as it has another system.
Standard stereo isn't bad at all so unless you are a sounds fan it may be fine for you.
As said, Dynaudio is the optional factory stereo upgrade, comes in about £530. However it's not yet available for the mk7 R due to complications fitting elements of it into the centre of spare wheel well. The boot space is smaller than a gti because of the Haldex 4 wheel drive system.
Dynaudio is rumoured to be available from build week 45, BUT then vw originally said it would be bw22 and no joy, so who knows??