I did some searches and found this:
S62= 158kg or 348lbs E30/S62 Swap:
http://www.***********.com/content.p...-into-E30-Swap
note: ****= Bimmerpost
S65= 202 kg or 445lbs
http://en.wikipedia.org/wiki/BMW_S65
Seems that doing this swap would actually make sense from a weight advantage. -97lbs