Whats the difference between a ys1 lsd and regular ys1?
A Lsd.
:rimshot:
BA-DUM-CHING
you may want to elaborate your question a little bit… 
it’s similar to Posi track but for fwd, and it’s a component thats actually in the transmission. no more 1 tire fires! if you have the opp to pick up a ys1 w/LSD then DO IT! I have one and love it!
actually, its not just the lsd itself, but, the final drive has more bolts holes than a non lsd, usdm tranny. this is the main reason why one with a YS1 lsd, can’t add an aftermarket f.d. kit.