I've spec'd a 1000HP engine build in the LS2, nothing yet for the NSX, but the principles are really the same.
Definitely upgrade all of the bolts to at least an ARP2000.
I learned about the different piston options when my factory pistons in the GTO finally cracked and melted from the supercharger. It was expected.
If I wanted to focus on any FI applications I would go the route of the 2618 alloy.
The "4032" performance piston alloy has a silicon content of approximately 11%. 4032 is a high-silicon, low-expansion alloy. Pistons made from this alloy can be installed with tighter piston to bore clearance, resulting in a tighter seal with less noise. 4032 is a more stable alloy, so it will retain characteristics such as ring groove integrity, for longer life cycle applications. Relative to 2618, 4032 is a less ductile alloy, making it less forgiving when used with boosted and/or nitrous applications. This means that it expands less than a piston with no silicon, but since the silicon is fully alloyed on a molecular level (eutectic), the alloy is less brittle and more flexible than a stock hypereutectic "smog" piston. These pistons can survive mild detonation with less damage than stock pistons.
The "2618" performance piston alloy has less than 2% silicon. This alloy is capable of experiencing the most detonation and abuse while suffering the least amount of damage. Pistons made of this alloy are also typically made thicker and heavier because of their most common applications in commercial diesel engines. Both because of the higher than normal temperatures that these pistons experience in their usual application, and the low-silicon content causing the extra heat-expansion, these pistons have their cylinders bored to a very loose cold-fit. This leads to a condition known as "piston slap" which is when the piston rocks in the cylinder and it causes an audible tapping noise that continues until the engine has warmed to operational temperatures. These engines should not be revved when cold, or excessive scuffing can occur. 2618 is used for extreme-duty racing applications such as NASCAR, ALMS, Formula 1.
I spoke with a lot of the piston makers that offer both 2618 & 4032 and they all said that the 2618 will give a larger room to forgive detonation (either from bad tune to failed injectors, etc.). What was conveyed to me is that while the 4032 is stronger than the factory hypereutectic pistons, they can still crack and shatter like my pistons. I also had to replace the head since the piston pieces bounced around in there.
2618 will bend and dent, which in a sense decreases the compression ratio in the problematic combustion chamber. So think of it is self-healing counter measures for mild detonation.
Pics of my
Ferrea forged valves which seem to be the only ones that will bend instead of break off in the event that u over-rev ur engine from a mis0shift and the piston and valves "make-love". It's better than the head of the valve breaking off and bouncing around in the combustion chamber, which would be much more destructive to the entire engine. They have some VERY tricked valve design and materials like titanium.
I've evened upgraded to their beehive shaped forged valve springs (they have double springs too, but that will have more para-static HP loss from greater spring pressures.
Heads and pistons are ceramic coated with the 55% thermal transfer.
