ORIGINAL: sh0wtime
if you mean the XRAY active diff [link=http://www.teamxray.com/teamxray/news/newsdesc.php?news_id=1305&kategoria=1305&Xnet_Sess ion=adc7d9c4b824ce0cd1fa9a38c526b791]SHOWN HERE[/link] then yes they do make a diff that locks up on power
so do BBF, who have made Tactyl diffs for most poular cars for a few years now as have Fioroni with their Tractive IV diffs
basically these are powerlock or varilock diffs that just lock up under power but run fairly freely off power, the locking action is tunable by the use of ramps of different angles which is explained at the bottom of the XRAY link i posted above
however, they are NOT 1way diffs like the original poster asked for but they are probably the closest thing in on power operation & feel available to us at the moment
a good page explaining varilock diff operation [link=http://www.variloc.com/variloc_theory.htm]HERE[/link] [:-]
I ran these BBF tactyl front & center diffs back when I had K-cars & they work VERY VERY well on looser surfaces. When I say very well I'm talkin a few seconds off my lap times starting the day I put them in. I would love to have some now but they are difficult to get in the US now days.
Back on topic the one-way will make the car cut around tight corners very quikly and you will have zero off power push but there is the breaking issue (no front breaks).