A stock pipe KT-100 is around 18hp, so figure a 4 hole can somewhere around 14? A stock Animal is listed at 15.4-16hp. The animal is more "torquey" but has a far narrower powerband, so with the KT's overrev capability, the winner would really depend on the track configuration. I would expect a big oval to favor the KT-100, and a paper clip the Animal. On sprint, it would again depend on how tight the turns were and how long the straights... Why the World Formula (essentially a tuned Animal with an on-board starter) wasn't more popular, I don't know. It was all of the ease of a LO206. Before its' time, I suppose. KT's are on the way out -- KA100's and VLR100's taking over.