[Mr. Magic]

I'm pretty sure the 4-wheel active steering would help the 550i handling making it feel much lighter and eliminate understeer tendency. I tested with and without, and it makes a big difference. Unfortunately, this option seems to come on the Infinity Sport's package. But for BMW, 4-wheel steer (IAS) is an additional option not widely available on dealer stock inventory, and most need to be custom ordered.

Although these packages tested are what's widely available at dealers, I would have at least noted BMW offers the 4-wheel steer for an additional $1750, or better yet - tested it's difference and noted it, along with the availability and pricing differences.