I'm finally buying my first Jag (used) this year, but I'm getting conflicting information about the 2010 XF s/c:

Some sellers list the XF s/c as having 500hsp, while others list the XF s/c as having 470hsp. If the seller claims in their XF s/c has 500hsp, are they misleading or ignorant to what they are actually selling?

Also, is there any certain mileage threshold I should not pass when buying a used 2010 XF s/c? (eg. not advisable to buy this car if it has over 100k miles.)

Thoughts?

The early US XF SC (2009?) was quoted at 470 PS, then I think later on it was bumped up to 495 PS. The XFR which came out in 2009 was always quoted at 510 PS, then in 2013/2104 the XFRS came out with 550 PS.
PS is the same as DIN or metric horsepower, but is not quite the same as bhp, the conversion figure is .98632. Although most car magazines, sellers and even JLR use the PS figure and call it "horsepower". Yes, it is still horsepower, just not bhp.
So, for example, the 510 PS of the XFR converts to 503 bhp and the 550 PS of the XFRS converts to 542 bhp.
They are all the exact same AJ133 5.0 V8 supercharged engine, just with different factory tunes.
There is also some evidence that the 495 PS engine really had the 510 PS tune, same as the XFR.
It's all pretty moot though between the 470, 495 and 510 PS versions as it would be hard to tell any difference through the seat of the pants, it's not until you get to the XFRS that much difference is noticeable.
I wouldn't worry about the advertised bhp figure for an XF SC, just look for one in the best possible condition.

In the USA, we started getting the XF in 2009, never had a 2008.

In 2009, the only engine size was the 4.2L and it was in 2 variants, N/A and SC.

In 2010, they offered 2 engines, the 4.2 in the N/A (standard Luxury model) and the 5.0 in both N/A (Premium & Portfolio model), 5.0SC, and 5.0R.

I don’t think the USA got the smaller 4/6 cyl engines until 2013.

If I recall correctly, the 4.2L N/A had 300hp, 4.2SC 420hp, 5.0 N/A had 385hp, and the 5.0 SC had 470hp and the R had 510hp. The XFR-S was introduced to the US market for model year 2013 and rated at 550hp.

And I second Oz’s statement. All 5.0SC engines are exactly the same. Only difference is tune.

It seams like the US is always a year behind the rest of the world

to answer the question in simpler terms,

if the car is your basic XF Supercharged (it will have a supercharged badge on it), its 470hp.

If the car is an XFR (says R on it, different bumper, rims, R on the seats). its 503hp

I do have XF supercharged with 503bhp but there are no R designation anywhere.

then how do you know you have 503bhp? none of the XF's unless it was an R had 500+

I have 420BHP SC and seats /front panel R designation. I think Vytautas Stasiukaitis can get R seats easily

The USA is one of almost 200 countries where this car is sold. Marketing is tailored to most of them individually. In each market they set model designations, engines, standard and optional equipment, etc., etc. independently of other markets. I find no reason to doubt that in some markets the 510 hp version is marketed as XF Supercharged.

I found an option in Topix:
ENGINE TORQUE-625 NEWTON METRE