You can extend the factory warranty from BMW to get effectively the same coverage as a new one, but for additional years/miles. Aftermarket's warranties may be cheaper, but they may or may not have the same coverage. The factory warranty extension is less stressful trying to decide what's covered and getting it fixed as there's only one point of contact rather than the dealership and the insurance company duking it out with you in between.
Not having driven one with active steering, I can't say how it might transform the car - I find mine fine for my purposes. I might be spoiled if I did...no need for that now!