That was my experience when I sold my MkIII LS400. Never really thought I would get another one - hey ho!
Actually owning one is the only way to fully appreciate how good they are. They compare very favourably with most modern cars. If you compare them with other cars of the same age, they are just incredible. The ride is my favourite quality along with smooth gear changes and ample acceleration. Economy is more than acceptable for a 4.0 litre V8 - much better than you would get from a Jaguar of similar vintage. Buy as new as you can afford with a service history and you will not regret it. I drove mine yesterday and thought, this car cost £48,000 in 1998 and I am the owner!
Would you consider a Rolls Royce of this vintage? I certainly would not because of the £££££££ signs you would see coming out of your pocket. If you do pick a Lemon you will be VERY unlucky. So many people on this forum have sold their cars with regret and bought another one. They are also very reluctant to sell to upgrade.
Good luck with your search and keep us all posted.