good question! I´ve got them on my 1100GS. The protectors itselve are from ACERBIS, just the spacers between handle bar and protector are from Touratech(same as wunderlich). If you have the possibility to use a milling machine, you can built the spacers by your own and buy the original ACERBIS protectors.
The big advantage of the Touratech protectors are the spoilers! The ACERBIS spoilers are too small for the BMW, they are o.k. for summertime. The Touratech spoilers are larger, so that your hands are better protectet against rain and cold wind.