A corbon prop is not going to make a difference in most applications on a .46AX. Carbon props are normally used for high performance engines such as very high RPM racing engines, or (in much larger sizes, think bigger than 25%) aerobatics. An expensive carbon prop is only beneficial if you are losing performance from a prop that can't handle the loads your engine puts on it, and a .46AX just isn't going to over stress most sport props. Most likely, you would do just as well using an APC, and if you really need more power, upgrade the engine.