Rebuild, or build up?
If you're going to do any machine work you'll always want to rebuild the bottom end, but at 450-500 hp you don't need anything extra beyond a good rebuild. I always have my cranks checked, and turned if needed. I also have all block mains align bored; it's cheap insurance. After that it's just new bearings of good quality. Any good machine shop should check bores and either bore or hone them to whatever piston you'll be using.