Do a search on this though, you don't just need the Diff itself...you also need a bolt kit or something, I can't remember off hand...but the parts total up to about $600 before labor...That is the cheapest "real" (by real I mean non phantom grip) LSD you can get...and it drops right in...
IchBin, you have a G-15M-R gearbox if you own a 5-speed...yeah this and another LSD will fit the G-15M-R, but if you own an auto you are out of luck...