Hi Welcome to the Jaguar Owners Club John. Diesels should tow a caravan no problem. However, you may need to check with your dealer if the transmission needs a cooler. I am not too sure if one is needed or available, so worth checking. S-type is more refined but the X-type is still a nice car. The S-type is bigger as well. The X-type was a competitor to the Audi A4, BMW 3-Series and Mercedes-Benz C-Class as the S-type is more of a competitor for the Audi A6, BMW 5-Series and Mercedes-Benz E-Class and CLS-Class. As you are towing then you should be aware that the X-type comes in FWD and 4WD versions and the S-type is RWD Let us know how you get on :)