Yes that's it!
It must be heavy as heck because it's REAL slow at 9.7 sec 0-60 mph. Plus they only gave it the 5.0L NA engine which seems a bit off as I would think you would want the extra power for emergency situations? They did add the larger disc's from the SC version.
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Exactly what I thought - so I was looking to see if they did a faster sentinel in late MY's or how fast the MB S600 Guard is etc. That maybe only 9.7 secs etc. in B7 protection, when B6 should be more than enough unless you are up against terrorists. But would B6 be appreciably any lighter?

 

B6 is a lower level of protection but any of the articles I have read just mention the one version of the car and that it meets the B7 standard.
I don't think you can get one with the B6 rating?
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I don't think it would be easy but unless I am mistaken, many of these companies offer after market conversion...

So how about a V12 Supercharged Sentinel?

 

I just bought these 2017 Jaguar XE 18" wheels anyone know if they will fit on my 2015 XJL

2017 18" Jaguar XE Winter Rims and Michelin X-ice 245/40R18 Snow Tires

 

I have 18" rims for winter tyres. Michelin studded X-ICE 4, but in size 245/45-R18 in all corners. (same rolling diameter than original summer tyres)
The Jaguar rims should fit directly, but better to test in front first if the caliber touch the rim or not. I have no-name rims, and there are about 1mm space between caliber and rim.
When you test them, note that do not use anything else than hand for the bolts first until you are sure that there are enough space. If you use powertool you can bend the rim against caliber if there are not enough space.

 

Those look very nice - great find. From what I have heard 18" fits, but you will need to check...

 

What if I go with 245/50/R18 tires that would be more comfortable?

 

The winter tyres have all much softer sidewalls than summer ones, so comfort are there anyway. You will find that they are less noisy too.
Best option are to keep same rolling diameter than originals, to keep speedometer correct.
This are one of good tool to compare different tyresetups: https://tiresize.com/comparison/

 

I plan on changing the winter tires to all seasons I am down grading to 18" rims from 20s to get a more comfortable less road noise drive if I keep the same diameter of originals I don't see the point only difference will be smaller rims

 

Yes, With 18" wheel you will have much more better drive. (in fact pretty much only benefit for 20" is visual and of cource thats only matter who likes what) You will naturally need more sidewall for the tyre when you go for smaller wheel to keep overall rolling diameter same between 20" and 18".
With the tool on link you can add your OE 20" size and compare different width/height aspect rations on 18" wheels to find the size to have closest rews per mile. Also tyreshop are propably happy to help you to find correct size.
Note that the with/height values on tyres are an aspect ratio value, so the wider tyre have higher profile, even the value are same. (thats why OE 20" have /35 on front and /30 on rear)

Edit: The OE wheel/tyre sizes are also printed on the tyre pressure sticker located in driver door frame. That sticker include 18", 19" and 20" OE variants.

 

It sounds crazy but don't overlook Pirelli Scorpion AS Plus 3 and also their new UHP to rival the Continental Extreme Contact DWS 06 plus, the Pirelli P Zero AS Plus 3
https://www.tirerack.com/tires/pirel...pion-as-plus-3 With those I am looking to increase the sidewall at expense of a little width, i.e. 235 55 19 front, with 265 50 19 on the rear, or close to...

But then again I may say screw it and stick with UHP or UUHP with one of the very best of the two of each IMHO listed below for you...

Likely the two best UHP All Season: -
https://www.tirerack.com/tires/pirelli-p-zero-as-plus-3
https://www.tirerack.com/tires/conti...ct-dws-06-plus

And, similarly for UUHP or "Max Perf. Summer": -
https://www.tirerack.com/tires/michelin-pilot-sport-4s (a legendary tire)
https://www.tirerack.com/tires/conti...ntact-sport-02

Also the Michelin Pilot Sport 5 is new and very interesting, a bit less sporting than the Pilot Sport 4 S
And these interest me greatly with the N-Spec - look deep into the reviews and you will see spirited drivers prefer them over the DWS 06 Plus
https://www.tirerack.com/tires/miche...t-a-s-3-n-spec

But in all likelihood when the time comes I will probably get the Scorpion or the P Zero AS 3, as I have had great success on my Mercedes CL with the latest Pirelli getting unbelievably quiet and smooth rides. I think Pirelli are now well ahead of Michelin in that regard overall.

Hope that gives you a few pointers based on hours of research, along with these videos: -