The bolt on adapters come with a slip on spacer incase you can get away with more rack travel (frame/tension rod clearance, no over-centering)
The rack will need to be recentered regardless of what you do. You can simply remove the steering wheel after following this procedure:
http://www.nicoclub.com/FSM/240sx/91-94/ST.pdf
Edit: You cannot use the measurements given in the FSM as you will be changing the length of the rack. You can turn to full lock, measure how much rack is protruding, divide that distance and that is your center position.