I just bought a fmf fatty. I'm going to go with a fmf q seriers silencer. Ken recommend toomy but they are $$$. Carb is going to be a kiehin D slide 34mm. Ken is going to do the rest.
I will probably do the 400ex rear shock right away since its such a cheap and easy mod.
Down the road I will get an extended swing arm. Not sure what length I will go with yet.
I'm not sure if I should go with a 13 or 14 tooth front sprocket. I'm sure it will have plenty of power to put a 14 in it but it might be too tall in first to start out.