If you're just going to swap the front end to S15 anyway AND change the motor, why buy the 97/98? It will be of no benefit to you except less miles on the body.
I say go with the 95/96 style, save the cash and do your mods. You won't be able to tell it from a 97/98 in the end anyway. <img src="#/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>