I split off and expanded an existing section of a site to create a new website. I want to move the old section to the new website and I'm wondering what the best technique is for SEO. Is it better to leave the old section on the first site and then add links on the old pages that point to the corresponding pages on the new site? Or, is it better to do a 301 redirect to the pages? Would there be any negative consequences for redirecting from one domain to another domain?