What year is your Jag? If it is a 1998-2002, you can swap your rear differential out for a 28-spline 8.8 from a 1989-96 Thunderbird/Cougar, 93-98 Lincoln Mark VIII, or 1999 Mustang SVT Cobra. The SVT Cobra has LSD already; the others do not, except for an 89 - 96 Thunderbird Turbo Coupe or...