For what it's worth, I bought mine 3 years ago this month, for only a little over the so-called invoice price (which I'd researched at edmunds.com). The dealer knew I was looking for a 6-speed and called as soon as the car hit the lot from the factory. There were no cash incentives at the time and, if I recall correctly, never had been on Challengers. (BTW, if there's a low-rate financing incentive, you can always use that to negotiate a lower cash price because there's no such thing as free money.

)
Anyway, my point is, if what I experienced is any indication, now would be as good a time as any, except when the refreshed '15 models hit the lots, the leftover '14s will immediately become 'old', more than ever before.