After 18 rounds, the season reached its finale at the Interlagos circuit at Brazil.
Although the track has its challenges, overall it sits as a medium downforce circuit along with most other recent venues. With the teams having an eye on reliability to preserve their championship points - or some teams having stopped development to focus on 2006 - there was little development to be seen in Sao Paolo. In fact, most cars were in very similar specification to the updates first seen back in Turkey.
However, the drivers with a fresh engine for this race had a unique opportunity to have their usual two-race specification altered to last just one race. This meant drivers had more power and revs available for the weekend, and Cosworth for example had their engine duty cycle revised to allow the full 20,000rpm for the whole race, although the accidents for both Williams drivers prevented this spectacle in Cosworth's last race.
Interlagos is one of only two anti-clockwise tracks, and while this makes little difference for the cars, the drivers suffer more in the neck area - after already being wrought after a season of racing.