I wrote this for another forum. Figured it might be worth posting here for peoples reference.
It was very difficult to copy from the forum so here is a link to the posts.
http://www.e30tech.com/forum/showpost.php?p=1362733&postcount=1
http://www.e30tech.com/forum/showpost.php?p=1364179&postcount=427
http://www.e30tech.com/forum/showpost.php?p=1364186&postcount=428
Wow nice elaborate piece Gunni, thanks!