I'd say that is a pretty good price. I use a GM 110# spring (part number in signature) and it works fine for me. Did the spring come with a spec sheet and a recommended install height? If it didn't, I would request a one from Kirban and install per recommendations.
i email kirban about a month ago and they responded that they are 95# springs and are perfect replacements. and also a kid at our local dyno day had them on a 120k car and worked great so i bought them and installed the over the weekend. But the driveshaft is out so i havent started it yet.