Mini quads are awesome. So durable, and so much fun. I wouldn't call this "racing" - it's just tooling around like idiots - but that doesn't make it any less entertaining.
We are flying custom made frames (http://untestedprototype.com) with Openpilot CC3D and Naze32 control boards. Video is all 5.8 - mixture of Fatshark/ImmersionRC and Boscam. We got a fair bit of interference but flying through it is part of the challenge and fun.
The music is an old jam with friends called Lap 17. I'm on bass.