The price will probably not go down. The Euro has appreciated significantly against the U.S. Dollar. At ~1.50 EUR/USD, BMW gets less Euros per car they sell in the U.S. than they did when the Euro was at ~1.25 EUR/USD, cutting their margins if they sell for the same U.S. Dollar MSRP. I think there is a larger likelihood that the price will go up.
That said, I would absolutely wait a couple extra months for the LED lights and other potential updates.
M3 Sedan - AW/Black - 6MT - no moonroof - no folding seats - RAC RG63 - clear bra by Omega Werks