Well I definately don't have the Road Tech. I thought a 660 Zumo was the same unit. So I bought one used instead of $900 here in Canada for a Road Tech.
That said, it boots up and shows the directions on the screen. I assume you're positive that it won't match up to the HD chrome bracket and come out the speakers?
Will it give commands through it's own speaker when installed on the bike?
How about blue tooth directions through a bluetooth headset?
Many people have thought the exact same thing, but they are not the same in firmware, but everything else is.
It will give directions through it's own speaker, but I don't think you can hear that riding down the road, the Bluetooth part I have never tried, because I was one of the first set of people to have the NIM/iPod interface, when it didn't work, because they had the directions written wrong, spent a few days getting that worked out and HD fixed the directions with the info we came up with, anyway, I have always had the NIM so I never tried the Bluetooth other than for phone calls.
It will match up to any of the HD products for the RT Zumo's, it is the exact same housing as the RT's, all the 660 and 665 are the exact same housing and connections, whether it is the Zumo660/665 or the RT Zumo 660/665, the difference is the firmware that the units use, this is the reason it will not work with the NIM. It will fit any dash, handlebar mount/charger anything, it just will not cut any audio sources going to the radio with the NIM, other than it's own, when connected through the AUX input and playing music stored on it.
I am positive that it will not cut audio sources and send directions through the speakers, but as I stated the first time, you can use a 3.5mm AUX cord and connect it to the radio, this will give directions through the speakers, but the only audio you will have this way, is the audio of the Zumo, so you can put songs on a SD card and play them from the Zumo and then it will cut it's music and give the directions through the speakers when they are given.