Googling around I am seeing the stock LSD seem to be 45-60 lbs, gravel rally cars set 150-175, and drifters shimming them up around 250. So using that as a scale 45-250 I think 100 is a fair start.
Link to Weir page, I have the #1 kit
http://www.weirperformance.com/maxgriplsdkits.html