Does anyone know if you can put coilover lowering springs over stock shocks in a 91 civic wagon and if it would be hard?

Ones like these:http://www.ebay.com/itm/191183574180

 

You should look into a wagon specific forum (or even search) to see how other wagon owners have done theirs. To answer your question though, those slip on sleeve coilovers usually come with an assortment of o-rings to fit a variety of shock diameters.

 

Wagon rear springs are longer than any other civic or crx. I put da struts and h&r race springs on my wagon and it was to hard for me on bumpy roads. Sport springs should be right for me.