I did think about waiting for this before I bought the E90, but then I looked at the engine range. It comes with a 140bhp 2.0D (too slow) or a 2.7 190bhp. Trouble is, the 2.7 is more expensive than the BMW 325D with less power and there will no discounts to begin with. CO2 is pretty awful as well. The better engines will come later, but at the moment the A4 doesn't have a credible engine range (well, compared to BMW anyway).
Not sure about the LEDs