just removed from my 2013 z4 2.0 a tmc tuning box which is plug and play increases bhp to 238 and increases torque also improves mpg. used on my car for a year with no issues had to sell the car for something more practical ,see link
http://www.tmcmotorsport.com/chiptuning-box-with-manual-controls looking for £225 ono posted
http://www.tmcmotorsport.com/chiptuning-box-with-manual-controls looking for £225 ono posted