I'm not an expert,but may be able to give some insight. Also, check out sportcompactcar's article on their 350z diff. or their website for more detail. Basically in a clutch diff they can control whether it works in acceleration and deceleration. A one way works only on acceleration, a two way both on acc and decel. Clutch type diffs can also control the level and speed of the lockup, so a 1.5 would be very relaxed on the decel side, but still have an effect.
Hope that makes sense, if anyone knows better i'll be interested to hear.
