What is the diff. from si ,dx,std rack and pinion ?

Im Rebuilding a 89 std h/b and i went into the auto parts store to buy my rack and the guy said what year blah ... what model and i said is ther a diff. and all he could tell me was it has diff. part # , what i would like to know if anybody out there could tell me what is the diff. from a dx ,srd, or si cvic / crx rack , im also putting a crx si tilt steering colum on , so will any rack for 88-91 civic /crx bolt up as long as it has no power steering ?

Thanks

MitchO