ok, first off.. are you talking about a real 180? or are you calling your 240 hatch a 180? Also a coupe 240 is NOT a silvia... this is a whole debate in itself....
Will it make a difference on your question, no not really, but it's really irritating when people call their car something it's not... if you really have a 180, how bout ya sell it to me? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>
edit: guess I read that wrong, you say you have an 89 silvia, dammit. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>
to answer your question, every RSTB i've seen for s13s goes either coupe or hatch interchangably.