According to IGN, the Street Fighter IV first expansion pack, dubbed Championship mode, is due to release next week on March 31st.
Replay Mode -- Record, upload, and download top matches to share with the Street Fighter IV community. Players can analyze top tiered fighters matches, leave voter feedback for others, and share their own triumphant victories.
New Points System -- Two new points systems to measure your skill (Championship and Tournament Points)
Enhanced Tournament Matching System -- Skill level matching system offers improved tournament match making for beginners and mid-level players. Competitors earn Grade Points (GP) to earn entry into more advanced tournaments.