Replacing the fans on a Replicator can be a real pain. I've published a simple replacement for the OEM spacers, which I've heard had been spawned by something evil:(http://www.thingiverse.com/thing:29030)

This is the next step. A part of something I'm working on and will make pulling the extruders apart for maintenance a joy... Well, I might be exaggerating a bit :-/

This makes a "deck" on which your fans sit. All the spacers are mounted exactly where they should be, so all you have to do is:

1. Set the heat sinks
2. Set the fan deck
3. Set the fans
4. Bolt it all together.

I tell ya, being lazy has its benefits.

btw, I dislike rafts and supports, so you won't need them.