Jesting aside, I think the 275 version has bigger brakes and stiffer suspension over the lower powered unit. From a performance POV, I found the smaller one just about enough for everyday driving but the 275 is more than quick enough. Same on fuel I believe.
Jag sell the 2.2 & the 3.0 diesels, both come with different power outputs. I believe the op is asking if there is any physical difference between the 3.0 & 3.0S?
Sorry for the confusion, I'm interested in the how the 3.0 and 3.0S engine which seems to be the same have different performance ( ECU tweaking, different turbos?, etc)
Also get the adaptive suspension, spoiler, seats from the XFR, different front end etc. the best way is to test drive back to back, I did and the S is a lot better.