I have installed mainfocus LED lights on my Z4. They are the same that fits on the E92 (Non OEM LED) that is those E92 2010 that came out before the OEM LED.
The OEM LED of the E92 (2011) did not fit on my Z4 35i
So far, I found that Carbon had the best LED light, but yet not matching the OEM 3 series LED...