[mgarblik]

I don't like them and only use them if nothing else is available. They are so extremely brittle, just a small amount of trace detonation can crack them, break the ring lands and cause other engine damage. Think of them as pistons made of glass. Lower end 4032 forged pistons are a giant step up from hypereutectic pistons. 2618 forgings are the best of course but might make a little noise in a quiet street car. In the overall cost of building a new engine, a couple hundred bucks for forged pistons gives you a much larger tuning window, room to grow your power, and lets you sleep at night.
On a typical V-8, if 400-450 HP is the goal, I would use stock cast pistons vs hypereutectic if saving money was the goal. They are not an upgrade IMO.

I should mention piston to wall clearance if your going to try a set. Make sure your machinist pays close attention to the instructions with the hypereutectic pistons. They run very tight in the bores compared to forgings. Typically, .0025" is the absolute max for a 4.150 bore. They generally prefer .0015"-.002". If the machinist sets them up at the typical .004-.005 like a low end forging, they WILL crack or fail in some way. Running so tight in the bore, an excellent hone job is required, torque plates highly recommended. Max taper .0003". Max out of round .0003". An awful lot of precision, time and effort for little to no benefit.