I am having a bit of trouble wrapping my head around their decision offer them stock ONLY with the P neck, but to sell J necks that can be purchased and installed by the buyer at his/her cost and risk. They should IMO offer them with either nec, from the factory.
No, this isn't a question of "I want them to offer MY custom option!" I understand they can only sell for low prices by having a stock set of features that all their machines are set up for. So, forget fret size, color, this or that option... it's not there and that's more than okay.
Here's the thing: they are already going to be manufacturing J necks that will fit the P7. So, in order to sell one that comes with a j neck installed, they won't need ANY additional machining or retooling; they will already be making these necks.
Why, then, won't they offer the bass with a neck they are already going to be making? Does it cost more to install a j neck than a P neck? No. All they need to do is have them at the factory where they are building these. Perhaps they will build the j necks somewhere far way, and would have to ship them to the manufacture location, whereas the P necks will be made onsite? Maybe. That's all I can come up with.
As much as I love Sire basses, (and I own 3), and as much as I have been wanting to add a PJ to the collection, I don't think I will be willing to pay $100-$200 more than the next P7 owner, in order to have the neck I want and which they will already be manufacturing. With the recent price increases, and then this added cost, I would hardly (if at all) save money buying a Sire P7 and an additional neck, versus just buying a Fender PJ that comes with a jazz neck such as the one pictured in this post, below (I know, I would not get the great Sire preamp with the Fender).
And, isn't one of the big points of buying a Sire to get a good bass for less money than a comparable one from another company? They'd be losing their calling card, with this weird plan for this new model. IMO that would be a mistake.
Just my 2 cents.