I have been thinking about selling my mini recently but the only information I can find about the value of it is based on the non sidewalk version. Can anyone point me in the right direction?

Any help would be greatly appreciated.

About my mini:
08 Sidewalk Edition Convertible S
White Silver
Barely over 36000 miles
Spotless and garage kept

Whistles and bells:
Harman Kardon stereo, Heated seats, Auto climate control, Retractable side mirrors, Auto on/off headlights, Rain sensing wipers, Auto dimming rear view mirror, Steering wheel audio/cruise/transmission/bluetooth controls, Steering column mounted tachometer w/trip computer, Universal remote transmitter, Sidewalk Edition leather seats, Sidewalk Edition rims, Fog lights, and a few things I have missed