Jaguar XK 4.2 Used vehicle

A wonderful good morning dear community, I play with the idea of buying an XK, but I don’t have the slightest idea what I should pay attention to when buying, therefore my questions to you: 1. Where are the weak points in the XK from year 2007 on? 2. Is a high mileage is to be seen? (from 150tkm – 200tkm) 3. Is a transmission oil flushing necessary? And if so, is this noted in the checkbook? 4. What is the actual consumption in the city? This one at over 17 l. 5. Coupe or convertible? I love both variants, just wonderful ^^ The problem with the convertible probably is wind noises, or am I wrong? 6. What would this fun have to cost me in the purchase? The price differences are enormous, from 14,000 to over 30,000 € everything is there. Everyone probably has his own price idea, but what is an XK actually worth until 2009? PS: All sellers I have called up to now assured me that no defects exist In addition, a dealer offers an XK 4.2 with “increased oil consumption”, then it ponders in me, because one can find this kind of deficiency neither in the workshop nor during a test drive. Thank you in advance and a nice week start I wish. Your Mr. Scht