In correspondence with Autoblog (and following rampant speculation circulating the Internet), McLaren spokesman Wayne Bruce confirmed: "Following a series of previews in which interest from American customers has been exclusively in the 570S, we will now concentrate on only this model for the launch of Sports Series in the US to satisfy demand."
That means the 570S will remain (for the time being at least) the most affordable model – if a term has ever been more relative – McLaren will offer in the US, priced at $184,900. We can also expect additional versions of the Sports Series to follow, including a roadster and a third bodystyle as well.
The cheaper 540C won't be kept out of North America altogether, though: it will be offered in Canada. North of the Border, the 540C is priced at $196,500 Canadian (equivalent to about $158k at current exchange rates), with the 570S going for $219,750 Canadian (~$177k).