I used to have an XJ8 Sovereign LWB, 3.2L V8 engine. I drove this car for 8 years. It was a great car, very smooth but a little underpowered.
Now I drive a 358 model Daimler Super Eight 2007 LWB Supercharged. For US readers this would be the same as a VDP V8 Supercharged.

I feel the suspension on the Daimler is much less comfortable then the 2001 XJ8. The newer car does not drive over small speed bumps (the ones you find inside parking houses) as well as my old Jag. The 2007 car seems to take them on much harder. The old 2001 XJ8 would just absorb the bumps. The new 2007 Jag will "bang" into them and not give as much as the old Jag. I have also noted that when I drive into my office parking garage the middle of the car will easily touch the pavement when I start the descent down the ramp (due to the abrupt transition from horizontal pavement to downhill ramp). The old jag would never touch the ramp in the middle of the car. I thought the old Jag was lower than the new Jag???

Now, the new Jag has much wider rims and lower profile tires than the old Jag. This puts the 2007 Jag at an disadvantage compared to the 2001 Jag with respect to comfort.
However, I would not have expected the new one to be as rough as it is.

The Jag 358 air suspension seems to level nicely as per the design but I wonder if the suspension is not adjusting up for slower driving like it is supposed to do? or something else is wrong with it.

Does anyone have similar experiences?

PS The Jag is unmodified

 

What size wheels do you have ? Comfort is best with 17" or 18". My X350 Sport had 20" Sepangs when I bought it, and I swapped them for 18". It transformed the comfort of the car.

 

Ditto what Fraser said. My 05 XJR, with it's 19" wheels, has a ride similar to yours. I've always wondered if the "sport" air shocks could be switched out for "comfort" air shocks without too much involvement. Does the Super V8 have "sport" shocks?
Wondered is the operative word as the expense of such a switch makes it out of the question in any case. The practical solution is smaller wheels, higher profile tires.

 

The wheels are 20inch and the profile is 40.

Is it possible to buy this design rim in an 18inch version? What is the name of this type of Rim?

 

Sure thing. 350 series Jag wheels came in 19" and 18" variations. You simply install 45 or 50 profile tires respectively.
.

 

Daimler,

Further to any plan you may have to go to smaller wheels; you want to make sure that any replacement wheels clear your brake calipers. I presume that your Super 8 has Brembos or the like and they do present a clearance problem for some wheels, Jag or otherwise.

Sorry old boy, but I didn't want to leave you with the impression that merely going to smaller whees was without peril. You must do your homework.