I made a lsd for my x-mod by packing grease in the dif-case. If you use hevey enuf grease you will get a lsd. I used the stock grease that came with the car and find it to light.I'm considering
going to crapy tire to buy thicker stuf and maybe try 5th wheel grease. If you try this becarefull not to get any grease outside the case. It would be like pouring tar in your car motor, so clean the out side of the diff-case before installing it in your car. this is one way you could make a lsd for your x-mod on the cheap.
the other guy's method useing plates sounds like a viscuse clutch diff and might be better than my idea. good luck.