selling an x5 ?

hi guys,
im thinking about selling my 2002 x5 3.0 w/ 6,500 miles
that or trading it in.
im interested in a 03 m3.

whats a realistic price or trade in value. i was looking at 43k or 40k trade in towards the m3.

configuration is as follows:
-black sapphire metallic
-20% metallized tint all around
-PDC
-xeons
-premium package
-premium anti theft sound system with 12 speakers
-sports package
-steptronic tranny
-sports seats
-grille guard
-lojack

any tips on where to list it.
to be honest i prefer the trade in because im not to comfortable with taking 40K+ in cash or doing all that paper work and wait.
but at the same time i dont want to be butchered by the dealer.

thanks in advance