James: I removed via a lockbar.. if you remove the steering rack you need to put something in its' place to hold the tierods (things that adjust toe and/or are used for steering) or the back wheels would flop about a hell of a lot
You can get lock kits such as the tomei one which retain the steering rack but use an arrangement of washers to lock the tierods in place.
Karina: Yes it will affect HICAS and the speed sensitive steering. When the little needle on the end of my speedo cable snapped and I thus had no speedo, I had to drive around with heavy steering until I put a new cable in when I installed my new dash.
I now have a lockbar in the back, no HICAS solenoid thing in the engine bay, removed all the lines. Have also got a 25 box and a 280kmh speedo, I get the HICAS light on the dash after 1-2mins of driving but my speed sensitive steering is still there.. I believe if you unplug the HICAS ecu in the boot you will lose the speedo sensitive steering..
Edit: oops just realised you said "odometer", does this mean the speedo still works but the odo doesn't??