Kellners Sport already has a map for the 20i & 28i for the factory ECU
http://www.kelleners-sport.de/en/New...wer_20-28i.php
X1 sDrive20i/xDrive20i, X3 xDrive20i, 520i, Z4 sDrive20i:
Standard:
max. power: 135 kW (184 hp)
max. torque: 270 Nm
Kelleners Sport:
max. power: 162 kW (220 hp)
max. torque: 324 Nm
X1 xDrive28i, X3 xDrive28i, 528i, Z4 sDrive28i:
Standard:
max. power: 180 kW (245 hp)
max. torque: 350 Nm
Kelleners Sport:
max. power: 216 kW (294 hp)
max. torque: 420 Nm