Absolutely the 97 by a long shot. The early years have ,so far, failed to show any real appreciation ,unless they have extraordinarily low miles. I would venture that the next most desirable RT-10, after the 97 Blue/white ,would be the ABS cars of 2001 and 2002. Follow that with making sure the cars have the factory top ( new suggested retail is $7000 for red or black tops only )so the car is a fully optioned machine and one should be in great shape.
PS - the hardtop was standard in 2002, yet many cars are being sold without the top and folks are being told they did not come standard. The reason is obvious, many of the tops are being sold on the side.
Bill P