I want to wire my new Garmin 550 to my 2008 softail delux. where do I hook it up to

Do you plan on hard wireing the power cord? This would be personal preferance, if it was mine I would splice/tap into a ignition/hot wire so when you turn off the bike power turns off to the unit. That way it would not be a constant drain to the battery. There are some hot wires between the tank by the frame just use a test light and find one that goes on and off with the key. There are also many variations of connectors to use. If you would not forget go diectly to the Battery but be sure to add a fuse to the wire to protect the GPS.