The one time I had a driveshaft rebuilt, it was a front one for a Suzuki Samurai. I don't remember the exact price, but it wasn't expensive. From your symptoms and patient history I suspect the driveshaft was disassembled and then put back together wrong. The two parts fit together many different ways, but all but one are out of balance. I'd take it to a driveshaft shop and have it rebalanced.

Oil cooler lines you should take care of soon. I've DIY'ed this one and give it a 6 out of 10 for difficulty.

Unless the car has been vegged, it's highly unlikely to need an injector pump. You could probably do with a rack damper adjustment. I know the motor mounts are fairly new, but they are worth giving a second look in case they went bad prematurely.

The suspension stuff doesn't have a very good description. I think you should get under there and inspect for yourself. Also, aside from the back being noisy over bumps, do you have any other symptoms? Drive funny? Wearing the tires funny? Pulling? Clunking? Just not feeling right?

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.