I have an RNS 510 C, MDI and 7P6 BT kit and I can't fault it. I was going to go with the Kenwood for £999 fitted by the dealers but I didn't want wires or a USB stick coming out the head unit as I like things hidden and once I priced it all up and fitting by Eddie NL it was cheaper aswell. Well worth it
Also I believe the 5K0 kits Eddie is selling are the newer version of the 7P6 iirc and its great, especially if you don't have a highline dash as everything is done through the HU