If you ride off road a lot the standard mount shakes themselves to pieces after 5000km of vibration (I had two under warranty). The TT mount (as much as I hate the company, thanks yet again for the 6 month wait for a chain guard Touratech Australia) holds the unit to the power and communication pins much firmer. Because the real advantage of the 660 is the phone, gps and entertainment system, (8 gig mini SD is a lot of tunes or talking books to listen too).