^^^ Good points Alan l. It's possible they are just offering pre-made harnesses just for stage 1 at this point to keep inventory costs down. The cost of four extra wires and a control box for Stage 2 and diy install to the consumer is much more cost effective on their end. It makes sense as a company to make that move if the product is not on high demand. Stage 2 is simple to install anyway so I'm not sweating it. My original post was to clear up the air for future buyers.
So to conclude, if you order direct from Burger, you need the stage 1 harness, upgrade to the stage 2 control box and USB cable. Return the stage 1 control box (core) if you want $20 back.
I'm sure when **********s or other vendors depletes their inventory of pre-made Stage 2 harnesses, they will have to resort to the same package mentioned above.