I finally upgraded my G2 with a GenX 2400 and like others i am now a satisfied owner. It's putting out much more dry skim then it ever has before, what a difference. I'm sure i'll get some stinky dark skim now.
Thanks to all those that have posted info about this.
I recommend anyone with a G2 to do the upgrade as IMO the sedra 3500 is just way underpowered. The needlewheel, ceramic rod, volute, all swapped nicely. The only parts you would need is a 3/4"slip to 1/2"threaded elbow and a small threaded sprinkler riser tube.