you need a lowering kit. get a $25 kit off ebay. its longer bolts for the end of the shocks. if you drop the bike off at a local indy it shop should run you 100-160 for install. i pulled the shocks myself and had the bolts pressed in for 40. bike looks dramatically different.
If you lower the rear you will want to lower the front. If not it will look like your bikes launching high in the front low in the rear. Arlen ness makes a kit that comes with everything you need and its the cheapest way to go as far as lowering the whole bike.