I also went from an X-type (2.5 V6) to a 58 plate 159 SW Ti about 18 months ago. Totally different car, Jag was great but I much prefer thee 159 Ti. I borrowed my cousins 147 Ti for 2 weeks while on holiday in Italy a couple of years ago, its much more nimbler than the 159 Ti and on small narrow roads more fun, but I wouldn't swap the 159 Ti 
