There's a few site's that sell a kit and you install it on a maxi-jet pump to get a LOT more flow out of them. We can't post links to other sites on here though. They are around $20 + s/h.
Might be a dumb question, but can you only modify it if it is being used as a powerhead in your main tank or can you modify the MJ if it is acting as your main pump. I'm asking because I am using the MJ900 as my main pump in my 14g biocube. If you can email me the website Travis I would appreciate it. fratboyey@comcast.net