For the Duke Cunningham special election, the turnout was
35.42%. California's other special election to replace John Campbell had only 24.21% turnout.
The R received 60,319 and the D received 55,587. The local party registrations are about 40% D and 60% R so the D overperformed a bit (getting 45%) while the R underperformed quite a bit (getting 49%). An independent candidate received almost 4% of the vote. However, he is a Republican who campaigned on the single-ticket issue of strong border enforcement. So, combining the independent and the official R candidate it looks like about 5% of voters jumped from R designation to a D vote.