sharing garageband files

I'd like to be able to collaborate with friends using garageband. I was thinking of giving them access to iDisk. I could then upload the garageband file, my friend could download, add his tracks, upload the updated version, i download that, add my tracks, etc.

One question I have is whether we need to have the same plug-ins. I have Guitar Rig, and I think some of my friends might too, but others don't. Suppose I lay down a guitar track with some Guitar Rig effects. Will my friend, who does not have Guitar Rig, be able to hear the effects when he opens the garageband file on his computer? Or will he just hear the raw input from my guitar with no effects?

Same thing with EZDrummer. I have it, but none of my friends do. Will they be able to hear the drum tracks I made with EZDrummer?