I had the 2150 connected to my HDS 8/10 and it was great. The AIS would overlay and you could even tell it to predict the course of the vessels for the next 15 or 30 minutes to let you know if you were in their way. Pretty cool. You can see the big Commercial boats or any smaller boats with a Class-B transponder from 20+ miles away.
One thing you may want to check with the HDS 5 units is that I think they may only have one NMEA 0183 Com port. I may be wrong here, as I've not owned an HDS 5 but I believe it can only transmit OR receive NMEA 0183 not both at the same time. That means you can EITHER send your GPS info to the radio OR receive AIS from the radio but I don't believe both. Again, worth a read.
That said -- fi that is true, there are two options. Standard Horizon has a newer model of the same radio called the 2200 that has the GPS built into it so it doesn't need to get GPS data from your chartplotter. It would just send AIS to be displayed.
OR, Lowrance makes a VHF that has a NMEA 2000 interface. NMEA 2000 is more along the lines of Ethernet and can send/receive simultaneously and is much easier to connect than the bare-wire systems.