I don't believe these wheels are fit for widening, I would prefer to use the OEM forged. However, cast vs. forged present no other durability issues, other than resistance to pot-hole impacts. And, in this case, the forged wheel would bend where a cast wheel will break. The end result is the same, yes? A trashed wheel? I'd rather trash a cheaper wheel.
As far as durability under power, I can't see a problem here either. IMHO, if you have enough power at hand to shread a cast wheel, your tires would prolly shread first. Effective warning sign?
I have a set of OEM forged Marauder wheels that have the factory clear coat removed, and the wheel polished. I agree with Nate, car washes use a soap much to caustic to the bare aluminum. But, a bit of elbow grease and they look fine.
Wasn't my desired outcome of this experiment, but the clear coat was going yellow anyway, and it was worth the time and effort to explore a way around this dull and off color appearance. Polished, and without any dull/aged clearcoat, the naked OEM wheels look as good as my nickle plated wheels.