There are 13 pages of write up on the link. A dyno run is useless to me, I ride on the street. A dyno run shows much less info than many days of riding with a GS-911 and datalogger.
If all you want is horsepower go another route, if you want better throttle control then any of the widebands will do that, programmed to any A/F R you want and for a lot less money. Putting more fuel in is easy, substantial horsepower gains need air, not so easy.
Hightechcoonass makes an excellent product, I have one, it is first class and works as advertised.
The OP asked for an alternative, the widebands, including PC V/ AT are far superior to the Wunderlich.