I have a 2015 Passat and it has the RNS-510 why do you think a 2015 Jetta has the older model?
Copied from VWVortex:
I have a 12 Tiguan SEL with Premium NAV (RNS510) latest version
I also have a 12 Golf R with NAV (RNS315)
The RNS510 is a much better NAV unit.
The RNS315 is much faster. The RNS315 does not offer internal storage. The RNS315 maps and smaller screen make it less usable for navigation.
My RNS 510 is not slow. It has NavTraffic and NavWeather and TravelLink. The larger screen and better maps make NAVIGATION much easier. The process to add stopovers to your route in the RNS510 is easier and more intuitive. I prefer the RNS510 because you get more data at your fingertips. Things that bug me about the RNS510 is that it cannot rip CD's to the internal drive, or copy from the MDI interface. It seems the only option for copying material to the internal drive is SD card. Copying to the Internal drive is infernally slow. I am putting 2.9 gigs on the drive right now and it looks like it will take at least an hour. Both units offer bluetooth audio with control. The RNS 510 has a higher incidence of breakup of the audio.
Both units lack a backup feature or history feature.
I am told you can upgrade the hard disk in the 510 to PATA SSD and get faster performance.
My two cents...