Normally I would say leaky injectors, but in most respects, the N54 and poor idle is the same as water is wet. I bought my car new with 1.3 miles on it, and the idle was crap then too.
However, new injectors doesn't mean the were coded correctly, or they sat correctly. Usually a leaky injector shows signs of fouling plugs in those cylinders.
Check your plugs, if they are all the same color, your injectors are probably fine, so you can rule them out again.