I understand ATTS is based upon hydraulics and LSD is mechanical.
Is one better than the other?
Which is lighter?
I've heard ATTS requires additional maintenance and is difficult to replace if it fails. Does LSD have these problems?

 

my type r has 72000 miles on it and i have had no problems with the tranny and i think that the lsd is lighter

 

I have felt them both and I prefer the direct DRIVER input of the LSD. the ATTS overcorrects sometimes making the prelude SH oversteer when it is inappropriate to do so. you can learn around this snafu, but the ITR tranny is so helpful you can throw the car around at will. I love it. I have a buddy with a 98+ 4.785 tranny in his GSR and it is AMAZING. It is very quick and as fast as an ITR for real now, no BS. I,H,E suspension tricks, brakes and proper tires... this is a fun car. the turn in is AMAZING and that LSD really seems to work well with the rear comptech swaybar and konis when set right, you can really throw the butt of the car around at will if you like... its total fun. LSD gets my vote!