NASIOC Thread
The price shown there is $549 for a "Deluxe" kit, which I assume means front and rear seats. The thread is also quite old, so I'm not sure how well it still applies.
I've e-mailed ATD, the guys that posted that, so see what they would charge for just the fronts, with the lower two panels of the seat back having a "gathered" or wrinkled pattern to match the stock SVX look, and the SVX emblem embroidered into the seat. Apparently they are distributors of the Katzkin leather kit, so you may be able to get a more direct answer straight from Katzkin.