I've been using QuickSilver since I got my Mac a few years ago.
What version of QuickSilver are you running that it's soo outdated? In March of 2010, a B58 revision came out, improving performance and I think improved plugin options.
Check the version of QuickSilver and make sure you're running B58. If you're not, go to www.blacktree.com to download it.