Audi will be refreshing the A4 and S4 this spring, with new models arriving shortly. Similar to the A5/S5 refresh, the cars feature updated front and rear ends and a few extra features detailed on Fourtitude. The following video shows some of the changes:

Quattro was made famous by Audi over ten years ago. After using it to dominate motorsports, they incorporated versions of it into its road cars, culminating with the torsen-based system found on the Audi A4. The system has changed gradually over the years, moving from a 50:50 torque split to a rear-biased 40:60. Torque vectoring was added in with the debut of the S4 sedan last year. Now at the Geneva Auto Salon, Audi debuted it’s new Quattro system that uses a new center differential. This is significant because Audi stayed with the Torsen center diff from 1996 all the way until this year. Whether this new diff gets put into the regular series of cars or remains an RS-exclusive remains to be seen.

The new center diff is explained in the video below, and also goes over the torque vectoring concept. The RS5 and S4 both come with torque vectoring, and is also seen on the new 2010 Porsche Carrera Turbo.

BMW Canada is offering two driving events that compare their 3-series against the competition. On May 27-30 and June 5-7 they will be heading to Downsview park and allow people two hours to test drive their car against the Audi A4, Lexus IS and Mercedes C-class. Granted, many of the competition cars will not be heavily optioned, and usually are run with very crappy tires, but it should prove to be a fun day. To signup go to their website.