1986 Jag Vanden Plas Good car or no?

Jaguars are some of the least reliable cars ever made. They may be pretty, and have nice features, but they break often and are very expensive to repair. Oddly enough, when shopping for a used Jaguar, you are better off buying one that shows normal or even high mileage for it's age, rather than one that has very low mileage for it's age. The low milage cars are often that way because they just won't stay running long enough to put on any miles. The mid 80's cars you mention are among the very worst for reliablility of any Jag model. Look outside any Jag repair shop and you are bound to see some mid 80's Vanden Plas cars covered in dust and abandoned over expensive repair bills. A used Mercedes or BMW is just as elegant, and both are far more reliable to drive and maintain. I've had both.