Well they're not forged and we've all seen those numbers you got there, but for how long? Just recently there were some folks on here talking about their 4.6 bottom ends breaking after running the 9# KB for a while. If you're going to add a power adder, spend the extra dough now and build the bottom with it. Spend 6K now and built it right with the supercharger instead of spending 3-4K on the supercharger, then spending another 3-4K and a bunch of heartache to fix it later.