They are fun straight line cars, but I wouldn't go trading off an SVT for one. They are quick (and even fast! - later models) in a straight line, but handling sucks and braking is downright scary.
86 & 87 are by far the prime years to have. However any year can be made fast for enough money. (though so can any car)
I wouldn't expect to switch cars and have it be a lot faster then the SVT off the bat.
Personally I'd love to own a GN, but not if I could only own 1 car.
It is on my short list of second cars though... I'm partial to Buicks...
