As far as I can tell, there will not be any group buy.
Eventually there will be a thread to buy the boards. Amp and power supply.
The rest probably will be up to you.
They had requests for group buys for the volume controls, silicon devices and cases, but that fell through.
At the moment the project is being made as easy as possible for us DIYers before being let loose.
And don't forget, when it is released and you have yours up and running, - show your appreciation to Kevin Gilmore, Spritzer and the other denizens for their efforts........