Here's one for the N63 engine, but listed for an X6 by Evolve:
http://www.evolvetuning.us/bmw/x5/x5...-ecu-tune.html
RennTech has something similar -
http://www.renntechmercedes.com/www/node/692
Keep in mind, part of what you're paying for with Dinan is the matched 4yr/50K mi warranty on the drivetrain.