E82 / E87 / E88 / F20 1 Series (2008 - 2014)
I finally got to take my 08 135i over to a dynojet dyno to compare numbers. The car made a good bit more power on the dynojet than it did on the dyno dynamics. My car made 320whp on a dyno dynamics and 353whp on a dynojet.
I then compared it to the JB4 piggy back set up. Peak number very close...