Hi guys I'm fairly new to this forum. I have been watching with alot of interest in regards to these issues as my 04 ST-R had steering issues when I got it 6 months ago. Mine wandered all over the road and the steering wheel felt loose, it seemed worse when wheels were not at dead centre.
I had a wheel alignment done and it helped a little but it started to pull to the right, then I adjusted my steering box and found it help alot more (still not great but better).
Jack your car up on stands so front wheels are off the ground, you can now feel how loose it actually is. Good time to check your wheel bearings as well (I found one loose). The steering box is directly under the battery, and I had to take mine out to get to the adjustment screw for steering box.
You will have to get under front wheel arch and move the dodgy dust skirt (not sure what it's called) that goes from the front of wheel arch, over top suspension arm and to the rear of wheel arch. Only need to take about four out front the front end and you should be able to get to steering box.
There is an adjustment screw with a slot in the top of it and a lock nut on the top of steering box. You need to loosen nut off, and if you move the wheels through full lock by hand while you are adjusing the screw with flat nosed screw driver and you will feel the steering firm up. You will notice the steering will lock up tight, once this happens wind the adjuster back out until the wheels move freely again, I only had to adjust mine in about 3/4 of a turn. Make sure you retighten the lock nut back up, I don't have the torque spec but I just did mine back up as tight as it already was (just by feel).
I only did this by feel, and if you do the steering box up too tight the steering will not self centre when you drive it. This happened to me and was very hard to drive, but all I had to do was adjust the screw out a little more and all was good. You can adjust it to suit your own needs.
Hopefully this helps someone, and hope I didn't confuse anyone. I isn't the easiest job and is easier with two people, just to help with adjusting the screw while moving the wheels.
Just a quick note on another subject, while you are under your car (I'm sure everyone is aware of bolts coming loose at random) check your fuel tank mounting bolts, I found one of mine missing and another loose at the back end. I could move tank up and down 20mm or more, could explain some of the mystery knocking noises.