Guys,
I'm new to Phantoms but not to quadcopters. I have several APM flight controller based quads and a hexacopter and I started out with the Ublox M6N gps units and they are OK. Probably the same class gps as in the P3S. I've since upgraded all my drones and fpv aircraft to the new Ublox M8N gps. Sure it's got Glosnas options too but the main reason I upgraded is the lock time is typically under 30 seconds cold start. HDOP are under 1.4 and the accuracy of the M8N gps is under one meter now, about twice as good as the previous iterations of gps.
I'm thinking that a Ublox M8N wired for Naza FC should work. I see no reason it wouldn't... the APM flight controller didn't do anything different when I upgraded to the M8N gps other than reporting more sats. and a much lower hdop. The data isn't any different coming out of the gps whether it's a 6 or an 8. Just more accurate data that syncs quicker on start up has been my experience in the APM world.
I can't just move one of my M8Ns to the P3S as the connectors are different so unless I read something concrete I'll be ordering one with the Naza connectors.