There has been some mis-information for a while about the E36 rack ratios plus I remember someone on here running an E36 3.0 M3 rack in their E30. I have spent some time doing some measurements plus confirmed this data direct with ZF (I know someone who works there who can access drawings on their system).
The standard way ZF quote on-centre (straight ahead) ratio is in mm/rev, which is the travel in mm of the rack bar per revolution of the hand wheel. The higher the mm/rev the faster the rack.
M3 3.0 - 39 mm/rev - the slowest available rack. This is a variable ratio but it is slower than standard until 200 deg hand wheel angle.
M3 3.2 and standard E36 - 45.5 mm/rev - the M3 3.2 rack has restricted lock.
Z3 rack - 53.5 mm/rev - by far the quickest rack you can fit.
E46 compact rack - 50 mm/rev - apparently this also fits the E36.
Because the M3 3.0 has a variable rack it has the smallest lock to lock at 3.0 turns but don’t be fooled it is the slowest by a country mile. A worthwhile upgrade for any 3.0 M3 (or a track based E30 with one of these fitted) would be to fit a standard E36 rack (or even a Z3 rack) which is what I did a year ago with a noticeable improvement.
http://www.bavarian-board.co.uk/forum_posts.asp?TID=25831&PN=1E46 M3 CSL - 3 об.
E36 Z3M Coupe - 3 об.
E36 M3 3.2 -3,5 об.
Е87 116iA - 3 об.
короче тока на 3,0 usa 3 оборота, тачка редкая - думаю рейку хрен найдешь, читаем англ каменты два
вывод - ставь 36 и не парься, е30 хватит за глаза ( по секрету - 36 молча плачут и ставят рычаги е30 даже ), а тем более с мотором 2,0