what rods would be better for my build

Unless something has changed since I was a process engineer and was responsible for the forged parts used in pressure vessels, casting and forging are two unrelated processes.

Casting melts the base material and it's poured or injected into a die (bye gravity or under pressure it's still casting). Forging takes a piece of solid material and beats it into a shape in dies (either cold ot heated). Because of the hammering process the grain structure is very small and is aligned along the surface and this is what makes a forged part so much stronger than a cast part. Forged parts also have a rougher appearing surface than cast parts.

There is a third process used for making connecting rods that the OEM's are using more and more an it's called sintering. This process takes very fine particles (almost powder like) of metal forces them into a die at very very high pressures.

I am quite sure some people have broken SIR rods and I guy here at work has a wallpaper on his PC of a broken Eagle H beam rod from his Mustang. Eagle is a reputable company that has an excellent reputation and I can't imagine them allowing it to be ruined by an inferior part. The SIR rod is a better piece than a stock rod and if you are looking for a cost effective way of up grading and aren't building a 500+ HP motor they are a good choice as is the equivlent I beam rod from Scat or a multitude of other manufacturers.