So basically when I get the shocks replaced they will come with new suspension (coil) springs as well? That should improve the ride height of the car a bit, which I suspect is lowered due to age. Seems like the leading edge of the front under tray is always scrapping a little whenever I come up on a hump in the road … 
Hah! You should be so lucky! No, you will need to use a spring compressor to separate the springs from the shocks and install the springs on your new shocks prior to installation.
Not too sure about that? Surely the weight of the car is being taken on the upper spring pan?
The springs are between the shock bushes
Yes but the weight of the car is compressing the springs which should relieve the pressure on the top shock mounts?
The weight goes from the top bush, thru the spring, to the other bush ,to the suspension arm.
And it’s a only a quarter of the rear sprung mass. So, say a 3200lb car with slight front weight bias might be 1700 on front wheels 1500 on rears so that would be under 400 per spring/damper unit, which have much fatter bolts than mere shock absorbers do.
If the front is scraping ahead of the front wheel spindles then raising the rear will make it worse. Now would be a good time to measure ride heights at each corner are to spec and use factory nylon packing shims up front and/or alloy spacers in back.
You can buy dampers with or without springs, as you presumably saw when you were first looking at replacement dampers in the original post (the ones I apparently wrongly assumed your car needed?).
There is a good argument besides cost saving for sticking with existing springs plus spacers, because sometimes new springs can be slightly the wrong rate and raise ride height too much, which is much harder to fix.
I have some front shims for the price of postage if you say how much lift it needs (the shims will be slightly less than that, due to lower wishbone geometry).
Yup !
The compressed springs over the shocks are the “load” I was cautioning about.
I know not as to what your body will allow. I’ve spent a lot of time under my car. But, not any more !! The years take their toll. If you can, get a look under the car and see how the rear suspension is “rigged”. If not go Google. “Jaguar IRS” or similar should get hits. Pictures or even videos!!
As to the “screwed up” hub. Why not get the old one. it isn’t a core for a rebuild…
I used old rotors from my F150 for various alternate uses. Weights, stands for devices, etc…
Ditto to Pete’s post.
Raise the rear and the front will be lower. Think seesaw, an ancient play ground piece.
VIZIO lives on. Got three of my electronics going all at once!! TV,. land line and cell !!!Twas a good day…
Carl
The springs on our Jags do tend to sag, as they are a bit underdesigned. However, before taking action, make sure all your shocks are good. The gas pressure in a good shock actually helps lift the car a bit, and this effect is more pronounced if the suspension is soft – which the XJ-S is. The XJ-S will ride almost an inch lower with dead shocks than with good shocks. So, if the sag is slight, you may find that renewing the shocks provides all the correction you need.
This certainly happened when I replaced the front shocks on my XJ40, the ride height went up <>1”
That only applies to monotube gas-charged dampers (which might be rebuildable). The classic twin tube type of shock doesn’t expand on its own.
Good to know, and thanks for pointing that out, Kirby. 
Whatever. The shocks that fit the Jaguar XJ cars are all gas shocks, they all lift the car a bit when in good condition. And so do the struts on my early 2000’s Japanese appliances, and they’re as cheap as they get, so it’s doubtful anybody uses non-gas shocks or struts any more.
Wash your mouth out for using ‘struts’ and Jaguar in the same paragraph LOL. You’ll be saying ‘rocker covers’ next…
I’ve got an XJ12, D-Type and E-type Koni, Girling an AVO shocks, plus a set of four rear XJ-S Girlings and a box of miscellaneous ex-Jag Armstrong and Boge - none of which would lift he car a millimetre.
But yes, my X300 has typical Bilsteins and Boges KYBs etc. do give a small lift and may well be all Atty needs.
I’ve developed a fondness for the Chevy LS engine, largely because of its rockers and the resulting .600" of lift!
I dunno about the shocks for the D-Type and E-type, but if those Girlings from the XJ-S don’t lift the car a bit, you might as well throw them away. They have lost gas pressure and it’s not really plausible to re-pressurize them.
Are you looking to get banned to the lumps list ?
OK, just once, since this is waaay off-topic:
Being rather wealthy in retirement, I got to thinking about building one of these:
https://www.factoryfive.com/type-65-coupe/
I put so much thought into it that I had worked out many of the details, including going through a litany of possible engines, starting with the Dodge Hellcrate on through the Ford Coyote in NA and supercharged form and on to the LS in various incarnations. Eventually decided I did not want a supercharger, then settled on the LT1 which is the engine in current base-model Corvettes. When done, the Type 65 Coupe would weigh in about 900 pounds lighter than a Corvette. I’m still trying to figure out where the Corvette puts those extra 900 pounds, since nothing about them looks particularly heavy.
Anyhow, I got wound up far enough in this idea that SWMBO had to put her foot down. No more project cars here. Oh, well, it was fun going through the thought exercise.
Being NV myself, what’s a SWIMBO, Kirby? 
Kirby… if you’re wealthy in retirement, the most obvious purchase is an XJS. How long has it been since you’ve had one, ten years? -John
She Who Must Be Obeyed.