Hi , the 1997 RR 4.6 came with mostly all the problems corrected so if I were you I would buy it with no fear , but you still have to take it to a dealer to check with test book if there is any hidden problems ¿?? And take a look under the car .Most problems on that model are the muffler they mostly get oxidation after five or seven years.
Do enjoy this car, believe me I do so very much with mine that is a 1998 .
Saludos .