It's made by Chris Sneed in the US. Wing is great, brackets OK. I have it through-bolted onto the boot lid frame - nice solid mount. Very light - they dropped the first one during manufacture and it fractured so they made a new one.
I find it helps at higher speeds, esp. sweeping bends. An angle of 2 deg. good for less winding tracks, 5 degrees for more corners and up to 7-8 degrees in the wet.
Drag is there for sure, but so is downforce. Look at the higher speed shots (blurred background) and you'll notice the slight front lift-off. It feels like it starts to work around 80-90 Kmh. Putting KW clubsports on shortly for hopefully will translate to less suspension compression and more contact patch.
I am planning to quantify my feelings with some timed laps and different pitch settings (including removal) at a Winton T & T day very soon.
PS - i only put it on for the track. Only the low-profile mounts stay on the boot lid.
2011 E90 DCT, ESS VT2-650 SC, Brembo BBK 380/345
AKRA Evolution system, RKP motorsport Lip /brake cooling ducts/diffuser, KW Clubsport coilovers, TMS race solid subframe mounts, performance seats/steering wheel, RMS harness, Sneed GT wing.