Airbox:
https://www.facebook.com/karbonius.fibradecarbono
http://karbonius.es/web_ing/producto.../base_bmw.html
The install of the Box is easy. You find some DIY videos on youtube.
I don't use the maf. I need a air-temperature-sensor.
The csl control-unit / snorkel is to long for the z4 engineroom and must be reduced.
The tuning takes place on a dyno.
Here you find some more infos of the karbonius box an there install.
http://www.m3forum.net/m3forum/showthread.php?t=480144