Hi Bob...
You shouldn't have any proplems with the Naza GPS and wifi, since it works on 2.4 GhZ like any W-Lan....
Here is two videos about the WiFi lag on GoPro:
....the Drift is in my opinion the "better" camera, but regarding the lag no different than the GoPro or the Contour. You won't be lucky to find a specific Drift gimbal....****, Tom and Harry are all on the GoPro / brushless gimbal band-wagon....your best bet would be to search for a gimbal which is more open to different camera models.
Chris