The yellow dot springs are for any 944S that came with konis, m030 or otherwise.

For 87/88 MY 944/944S/924S, the rear torsion bars are 23.5mm except with option codes m030 and m637, so check your option code sheet to be sure. In fact, I would visit this page:

http://www.944online.com/cgi-bin/ASI...tioncodes.html