You've seen the pro shooters out there with their $2000 1911 race guns do amazing things. Did you know that your humble Springfield carry gun, with a few tweaks, can hold their own rather well?
USPSA (for their Production class events) and IPSC both have XDs on their list of approved guns. Besides the Springfield custom shop, Barsto, Springer Precision, Canyon Creek, and others specialize in building competition grade XDs with Dawson or Sevigny Competition sights, smoothed triggers, improved guide rods, and other options.
Pros behind the XD
David Olhasso, a USPSA production class Grand Master, ran a stock XD and won the CDP Division at the 2007 IDPA National Championships (the first person to win that division with a polymer pistol). Olhasso is now a Smith man, but don't hold that against him.
Wyoming Police instructor Ara Maljian, another USPSA/IPSC Grand Master, has been known to often compete with an XD. Ara is also a big proponent of the XD replacing the venerable 1911.
(Photo from http://robleatham.com/wp/ )
He is a 24-time USPSA National champion and 6-time International Practical Shooting Confederation (IPSC) World Champion. He has been captain of Team Springfield since 1985 and is arguably one of the most dangerous men in the world behind the sights of an XD. In fact, the XD(M) competition model was designed Springfield along with input from Leatham.
Increasingly you see XDs, XDMs and even legacy HS2000-marked pistols make appearances in IDPA/IPSC/USPSA events across the country. Stock versions are popular in 3-Gun matches from Philadelphia Mississippi to Provo Utah.
Not bad for one of the most affordable carry guns in the market.