I've got the Koni's front and rear with stock springs in my ST24 (I've also got a larger rear swaybar). The difference is amazing. I've got the Koni's set about half way and the cornering is so much flatter and secure, plus the ride is actually better with them on the softest setting. Worth the money!
Here's a pic:
I imagine the ST24 springs would be very similar to a SVT's.