Thanks pjanczuk for track testing your car...now I don't need to thrash my 2000 XKR just to see what it'll do. I think the times, 13.41 108mph is pretty good for a 3785 lb car XKR Coupe). Now compare this to a C5 Corvette with LS1:

From Motor Trend Car of the Year 1998 Corvette:
345 hp 5680cc LS1, 3.42:1 axle, 3245 lbs curb wt coupe,
Quarter mile: 13.2/109.3 6 spd manual, 13.5/104.7 4 spd auto conv
The vette has a 550 pound advantage and a higher gear ratio vs Jag 3.06:1 and no positraction. So That's pretty good!

NOW Also consider this:
XK8 4.0 ltr 290 hp = 72.5 hp/ltr
XKR 4.0 ltr 370 hp = 92.5 hp/ltr
XKR 4.2 ltr 400 hp = 95.2 hp/ltr

LS1 5.68 ltr 345hp = 60.7 hp/ltr
LS2 6.0 ltr 400 hp = 66.6 hp/ltr
LS3 6.2 ltr 430 hp = 69.3 hp/ltr
LS7 7.0 ltr 505 hp = 72.1 hp/ltr : That's 427 cubic inches vs 244 for the Jag!!!
LS9 TVS Super Charger 6.2 ltr 638 hp = 102.9 hp/ltr
AND THE NEW JAG with TVS SC: 5.0 ltr 510 hp = 102 hp/ltr!!!

So all of you with an XK8 can be proud of the efficiency of a Jag with more HP/Ltr as the mighty LS7 - 427 Z06 Corvette:
And us XKR owners..well 92 hp/ltr is more than all but the ZR1 SC Corvette....HOW ABOUT THAT!