just as the title says i am wondering if jdm dc2 lsd will fit into a ys1 cable tranny and if so is it a direct replacement?

 

That's like putting a Type R LSD into the YS1 tranny housing. It'll work, but it's not a direct fit. There are parts that need to be shimmed in order for it to fit into the YS1 housing properly, but it can be done. Do a search and you'll see some posts of "how to's" with people installing them into their YS1 tranny.