for 450hp, you might consider some custom rods. I'm not saying the stock conrods wouldn't do 450hp, but you're really pushing them and I don't know that they'd last long at that kind of power level.
As for the pistons, you HAVE to get forged pistons as the stock, cast pistons won't even think about taking that kind of abuse. You can get them here for a fair price;
http://www.raceeng.com