Replace those Harley shocks now, they are crap (HD should be ashamed of itself). Koni, Progressive, White Brothers, Works and others make shocks that will greatly improve your Harley's handling characteristics.

"Short shocks are a compromise between ride quality and ride height. You give up the former for the latter. You also give up shock travel, which negatively affects handling. If handling is more important than looks, then you want LONGER shocks." -- Christopher deHahn

I raised my Dyna with great results using longer shocks and fork springs. The operation removed all wallow on the highway and kept the frame from slamming on the ground during hard cornering. This is the best thing I did for my Harley.

To lower an FX, Chris suggests:

"Relocate the shock mounts on the swingarm and/or frame to change the swingarm angle. Use high quality stock length or longer shocks. You'll maintain ride quality and handling while lowering the bike, at the expense of it becoming easier to ground out when riding aggressively. Same for the forks...use shorter length fork tubes and progressive springs. You want to maintain the shock travel."