Ford/Delco took over the Jag electronics by the early 90's.
I had an earlier '92 XJS V-12 that was absolutely beautiful and luxurious...and expensive to maintain. Unloaded it for the SL we have now, which is draining my pockets right now for a $7 headlamp bulb and $30 washer pump!
That is my typical experience right now...I can always expect to add a couple of zeroes if I get the Jag part versus the MB part.
One year, a broken glove box lock was $120! Same design as my $11 VW lock...except it had to be imported from GB due to having to specially key the lock!
The endless climate control and lamba sensor issues is what made my finally get rid of it. Decided $6K of repairs with less than 45K miles on the vehicle was enough!
Stuff like that wears you down.