If I want to lower a WRX, is it not a good idea with only the lowering springs? Is this setup bad to the OEM shocks unless you have the coilcovers?

 

You can do it on the factory struts, but I wouldn't suggest lowering more than 1.5" if thats what you want to do, and it will shorten their life either way. The right way to do it if you want to get lowering springs is to replace the struts with beefier aftermarket ones at the same time. Check some of the vendors to see what their options are as far as kits go.