Originally Posted by JCL

Perhaps my post #8 wasn't clear, so I will try again.

There is no single "E53 power steering" and the same is true for the E83, E70, and so on. There were standard power steering systems, and optional ps systems designed to change the assist level. Which is what you are asking about.

I don't have the full matrix of which options were offered in each year, but here are some guidelines. Options varied by market.

X3: standard ps, and optional Servotronic. Standard system varies assist level with engine speed. Servotronic varies assist level with vehicle speed, so you get more assist at parking speeds, and less on the highway. We ordered Servotronic as an option on our X3 and like it.

E53: standard ps, and optional Servotronic. Servotronic was (I think) included on the 4.6 and 4.8, and a priority one option on the rest. That meant a special order.

E70: standard ps, and optional Active steering. Active steering varies the steering gear ratio by means of a planetary gear set in the steering column. Ratio implies the amount of steering angle produced for a given movement of the steering wheel. Active included Servotronic, which wasn't available by itself. All of this will produce a very different feel.

M versions: special ps version called M Servotronic. User adjustable, I believe.

So, comparing an E53 and an E70 depends on which steering options, if any, each has. But a good guess would be that an E53 4.8 had Servotronic, and an E70 wouldn't, meaning the steering would feel much heavier at low speeds, but the same at highway speeds.

Jeff