I'm running the dual runner manifold and I can tell you that it's the best manifold to run with a stock turbo. Super fast spool up, noticeably more torque below 4K, and a little bit better MPG are three advantages I've seen.
Do some research and you can find some dyno charts that show how much difference we are talking. Yes you will need to set it up, but like Curtis said, it's easy and cheap to do.