There has probably more posts about the Twister and it's variations and the FP.40 than any other subject. Should be tons of photos also. The SIG Twister is a very capable airplane in stock form when built straight and accurately. The FP.40 will perform well also when properly set up and proper prop, and there has been tons on this subject also. The Fancher mods just make it "easier" to fly an accurate pattern, ion my opinion for lack of a better word. Notice that I didn't say it made the airplane better. I have recounted the story of a local guy using the same single , stock SIG Twister and several FP.40s to go from the Beginner class all the way to Expert class wins in local competition. If you build one from a kit, scratch build one right next to it as you go along. This will save you some time and money if you are just starting out. Make them exactly the same as you possibly can. There was a model published in Flying Models that Allen Brickhaus had something to do with that was called Tornado (get it, twister-Tornado!) and was a Twister with a simple box full fuselage. The Twister has been kit bashed into lots of different shapes, and is successful if you stick to the same basic "numbers" or "Fancher numbers" and make it look like anything you want. It's a very versatile design.
Thank you Mike Gretz!
Type at you later,
Dan McEntee