So the only difference between the newest GXII-5RHO and the one A Main has on sale is the three needle carb?

That three needle carb is pretty much the same carb GO made for the Arrow Racing engine, so it wouldn't be a disappointment to me not having it as I could swap one.... plus I'm very familiar with the standard two needle carb from my JS engines.

Who is selling GO parts in the USA? Will the JS con rod work on the GO engine?