I was hoping for more diverse siren tones but the ones included are adequate, I may try the MP3 version after my only favorite single tone gets old. (apparently different versions of 3 different sirens and the high/low chirp is actually half highs, and half lows) The momentary switch mounted on dash is essential for changing siren/chirp tones (both on same button) since cycling through the various tones requires that you know which Next one is to be selected and thus makes for many cycles through them all many times. All in all, a Nice upgrade but if you want fancy then go with the MP3 siren instead!
I ordered the Kenwood DNX6140. I placed my order on a Monday and had it in my hands on the opposite coast on Friday. Great service and great price. I was not able to find the unit any cheaper anywhere else. Sonic even shipped the unit out with all the adaptors I needed for the install.