The Eibach Pro Damper struts arent bad to use on a coilover conversion, as their own coilover kit uses that strut. Max spring rate is about 250lb.
However, their coil over strut has a threaded body instead of a coilover sleeve. Their rear shocks are not made to use with a coilover.

I used to have the Eibach coilover kit as my very first setup. Great kit, no complaints at the time and when I sold it to go with a GR40 Super Street Kit on my old car.