surely there was a problem with the springs then, meaning providing the springs aren't faulty they're not going to be terrible? did you take them back and get another set?
Thats not a personal attack but sometimes parts are faulty, I could slate Goodridge brakelines as on inpsection they looked fine, fitted them and the wire weave was faulty and expanded under pressure more than standard hoses. replacement set was fine, as with other Jamex springs I've seen fitted.