[strat61caster]

If they don't have markings on them then don't waste your time, put em into a project like above. If they do have markings on them that you can decipher they're probably worth $60/pair to someone who's interested in playing with spring swaps on coilovers that they will fit on, or hanging onto for your own suspension tuning purposes. Just buy BCs with different rates (you can custom order iirc) and swap the 10ks to tune handling, I'll be surprised as hell if they'll send you a setup without springs so you can save money.

10K is pretty stiff for this car, I had 9k rears for awhile and I don't feel like repeating the experience any time soon.