In the Contemporary Cobras we take the Jag front control arms and geometry and move it out to the track width we need. The tie rods are made a little longer and the swaybar gets heated and bent accordingly. Setting it up keep the lower control arms level and the tie rods should be parallel with them to minimise bump steer.
On the rear Jag suspension I recommend any modifications be done professionally per a procedure. The front and rear stresses can break lower control arms even on a factory part. The good folks at ERA have some great info on it here.
Shortening the Jaguar pieces
I have some parts available to help out the Jag rears also.
When you are setting up the Jag rear keep the control arms tipped down at about 3 deg to horizontal at ride height. Daze has some good info on the IRS forum.