I also upgraded the head unit in my Mk 5 to the RNS 315-i never used the sat nav,I only wanted it for DAB.
Went to town,stripping it all out to fit a genuine DAB shark fin ariel and a genuine upgraded speaker set-which needed crossovers from a scraper to utilise all the speakers which mine never had (8 speakers)panicked like hell at the pile of seats,trim pieces and bust clips-wondering if it would go back together ok.
It was fine and sounded great.
My Mk 7.5 has the Helix sub which I fitted.
This has better sound than the Mk 5,but there’s not a huge amount in it.
Vw Retrofit in Redditch was selling the Helix sub.
