There is a factory stopper on the s13 control arm that the steering nuckle is meant to hit. its fine.
I dont beleive a rack spacer will help when running s13 front end because as you have said, your steering is hitting the control arm.
just a note to this, u will notice when on full lock the steering nuckle is almost 'straight' inline with the rack end, any more lock and you would suffer very bad binding. any thoughts from guru's on this?
From what ive READ, i beleive "ae86 with power steering knuckles and lock spacer" is the best to use for largest lock. (havent had first hand exp, though)
I will be running s13 also btw.