Congress of Deputies results since 1989
The Alianza lost almost no seats (only 2.5%) despite a 5-6% drop in votes due to the electoral system. Now that this system is no longer constitutionally mandated, it would seem logical that the next government would do away with the system, replacing it perhaps with a regional MMP system (a measure I would not support).
The presidential elections
The failure of the Alliance to unite behind a single presidential candidate may have hurt its chances in the legislative race, but it did not affect the outcome of the election for the presidency. The leading candidate, Renovación Nacional's Sebastián Piñera, came out with just over 25% of the vote. The UDI's Joaquín Lavín, Alliance flag-bearer in 1999, took 23%, while the Concertación candidate Michelle Bachelet wound up with about 45% of the vote, meaning a runoff between her and Piñera (who likely stole many Christian Democrat votes).
The smart money is still on Bachelet to extend the Concertación to 22 years in the presidency, and be Chile's first female president, but the results indicate that it will be a tough race, much like the hard-fought 1999 contest.