I replaced all the steering connectors and suspension components except the lower control arms, which are still ok.

I have new tires and did an alignment. Now the play in the steering wheel is even more noticable. You can feel it knocking. I also noticed steering wheel shake. I can't believe it. On uneven surfaces the car just doesn't ride like it should. I have no idea where is it coming from. I suspect it is the steering column since I found this. http://www.bimmerboard.com/forums/posts/255559 I also found another post reffering to steering play and this person found out that the steering column was loose in both joints. http://www.bimmerboard.com/forums/posts/132089 After that he had no more play.

Do you have any experience regarding this issue?

Good crap. I'm so worried now.

My new control arms just got delivered, and replacing them and my brakes are going to be my Saturday projects this weekend. But now you have me worried that the problem might not be limited to those things.

bmwtransport, how would you describe the feel in steering before you replaced anything? How much play did you notice before you replaced the control arms?

I believe my steering is responsive, but I have some shake-n-shimmy at 50mph and as I brake. I'm worried that maybe my steering isn't as responsive as it used to be and I just haven't noticed because it has degraded over time.

After reading the links you posted, I'm not really sure exactly what parts are being described. Here is the quote:
The steering column being adjustable has 2 parts. The upper is rock solid encased in aluminium. This generally never goes wrong. However the lower part of the column (spindle)connects to the upper via a universal joint and to the steering box main shaft with another UJ. These are kept on with a pinch bolt. Once I had removed the trim and held the bottom spindle tight I could feel the play between the UJ and the steering wheel. I was delighted! I squeezed in a 13mm spanner (wrench) and a 13mm sprocket wrench and I was able to tighten up the bolt by 1 ½ turns. When I test drove it the difference was dramatic! This encouraged me to remove the splash guard floor plan from under the car and access the lower pinch bolt. This was also loose gain by 1 ½ turn. Whist under the car I also tightened the pitman arm bolt which tightened by ½ turn.
What's a "pinch bolt"?

Here is the lower part which I believe he is describing.
http://www.realoem.com/bmw/diagrams/q/l/132.png

Here is the steering box, the servotronic is labeled 5rs.
http://www.realoem.com/bmw/diagrams/n/u/4.png

Good crap. I'm so worried now.

My new control arms just got delivered, and replacing them and my brakes are going to be my Saturday projects this weekend. But now you have me worried that the problem might not be limited to those things.

bmwtransport, how would you describe the feel in steering before you replaced anything? How much play did you notice before you replaced the control arms?

I believe my steering is responsive, but I have some shake-n-shimmy at 50mph and as I brake. I'm worried that maybe my steering isn't as responsive as it used to be and I just haven't noticed because it has degraded over time.

After reading the links you posted, I'm not really sure exactly what parts are being described. Here is the quote:
The steering column being adjustable has 2 parts. The upper is rock solid encased in aluminium. This generally never goes wrong. However the lower part of the column (spindle)connects to the upper via a universal joint and to the steering box main shaft with another UJ. These are kept on with a pinch bolt. Once I had removed the trim and held the bottom spindle tight I could feel the play between the UJ and the steering wheel. I was delighted! I squeezed in a 13mm spanner (wrench) and a 13mm sprocket wrench and I was able to tighten up the bolt by 1 ½ turns. When I test drove it the difference was dramatic! This encouraged me to remove the splash guard floor plan from under the car and access the lower pinch bolt. This was also loose gain by 1 ½ turn. Whist under the car I also tightened the pitman arm bolt which tightened by ½ turn.
What's a "pinch bolt"?

Here is the lower part which I believe he is describing.
http://www.realoem.com/bmw/diagrams/q/l/132.png

Here is the steering box, the servotronic is labeled 5rs.
http://www.realoem.com/bmw/diagrams/n/u/4.png

It is a play that you can feel in your steering wheel. It's hard to describe it. I checked more throughly the steering today. I mooved the steering wheel while watching the wheel and it looks like there is about half inch if not more of play. I don't understand how can a mechaninc not see this...:confused

I can feel the alignment on my car is great now. Even driving over the little reflectors between the lanes are almost unnoticable. On the other hand... the car feels weird while driving over different kind of bumps or road imperfections. Very very strange after having all new steering connectors.

Anyway... now to your questions.

Before replacing arms, there wasn't play. It was shaking of the steering wheel and some squeaking noises. The shaking is common problem due to worn upper control arm bushings, but can also be caused by a stiff ball joint. Of course I thought it would eliminate some of the play. The worse ball joints were the horizontal ones on the center link.

Aa far as the column I believe these are the two bolts he is talking about. One located on the U joint on the lower assembly and the second one under the steering wheel.

http://213.215.107.73/fotoalbumy/033/689/f_33689509_34c56f620992c40c4f033a4d68691bb4.png