Ive been told there are no dumb questions, only dumb answers, so here is a dumb question: what advantage does a four blade prop give you over a three blade prop? And why stainless steel over aluminum? Thank you all in advance.
P.S. I know, it was two dumb questions.

A four blade lifts the stern of the boat and are good in rough water. A tad slower than a three blade.

A three blade gets the bow up so the boat is running more on the pad for speed.

A stainless steel prop gets a more solid bite in the water than an aluminum prop because at high rpm's the aluminum flexes and flattened out the pitch to lose bite in the water.

Thats what I have always been told. Maybe one of the experts will chime in and give you some more specifics.

In addition to what Keith said ,the stainless has thinner blades and can be cupped more agressively for performance.

One exception is that on a heavier boat usually the 4 blade will be faster because it has more boat out of the water.

Excellent! Thanks guys!

stainless can be cupped more cause of it's strength not thickness.
an alum. prop is not strong enough to allow the bend (cupping) before it cracks or breaks.

and on some boats, a 4 blade can be faster because of how it lifts the boat.