ok if you are a fan of the original Mazda RX7 you are probably in for a big surprise. Having driven only one RX7 around a block when I was a kid with a 240Z to compare the two cars, I think it's safe to say that the SVX and the RX7 are two completely different cars. The RX7 being a light, nimble little sports car you can toss around and have great fun with. The SVX, as one person said, is a luxury tourer with a sporty feel lots of power on the highway but only decent get up and go from a start. What the SVX offers that is far and away better than most cars, certainly an early RX7, is comfort, safety and a real great ride with enough sportiness that reminds you that you are driving a high-end sports car. To give you an idea, Last year I bought a mint 1981 280zx turbo. I love the car, it's fun to drive, feels faster than the SVX (but really isn't) but it does not compare to the ride of the svx. The 280ZX makes me a little tired to drive for long periods, the SVX is an absolute joy to drive.
Hope that helps.