The tuned pipe is definitely for speed. As stated above, your idle to wot time will be reduced but you must understand there is no in between per say! For 3D use a standard muffler or one of the tuned mufflers but there is no need for the tuned pipe. Prop range is of the 2 extremes. for a .46 3D prop is 12x4w and a pipe prop would be 9x9/10x8.