Uncle Melvyn Rutter has a very low mileage 1998 3.9 for sale.
http://www.carandclassic.co.uk/car/C519979Whichever you chose you will fall in love with - I've had two and I am hooked. Put 25,000mls on a 4/4 Sport in between the Plus 8's but had to return to that burble and seamless torque. My 1999 3.9 had 20,000mls only on it when I bought it last July and all I have needed to do is replace the rear wheel cylinders and shoes, front pads and a change of all fluids.
About 23mpg - we pass this way but once... quickly
Good luck with the search.
p.s. recycled teenager has seen the Perranwell Red one currently on the market - pm him if you are interested in an opinion on it I'm sure he will help.