I am very confused. I thought that the Swiftech MCP655 pump was supposed to be better than the MCP355 ... and it's more expensive. But in several places I have seen people saying that a MCP355 with some special configuration from petra's tech out performs the 655. What is the full scoop on this? I have been asking a lot of noob questions lately, I know. It's because I am a WC noob.