A nice upgrade to the 03 Springfield are the USMC improved sights, a thicker, higher front post and a larger rear sight aperture. S & S Firearms of Glendale NY have them on their website.
The higher front sight will require a higher front sight cover. Sarco used to have them but I have not checked lately.
Also Miltech of California sells refurbished Springfields which have been checked for functioning and look brand new. They are expensive but of excellent quality.