Evo 5 RS
I think (and hope) that the 5/6 will go silly once they hit 25 years old. They're the special ones in the range, have appeal worldwide and crucially weren't available in the US.
The 8/9/10 were all available in the USA from new, and I don't think will ever get the 'R32 GTR' price effect.
A 7/8/9 will still be an appreciating asset, as more and more rust away and get broken into pieces.
Guy F was saying that he really struggles to shift anything 7+. Everyone wants the 5s and 6s.