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:

While there have been a lot of test drive videos lately, this is the first head-to-head video I’ve seen. The R8 does admirably for an older car, and while people might not cross-shop the R8 against the 911, it’s probably people are considering a used R8 vs. one of the new Carreras which are the same price.

The facelift that affected the Audi A5 and S5 have “trickled up” to the RS5:

Audi just announced the new engine powering the Audi S6 and S7, and a variant of the engine will power the S8. This is a twin-scroll, twin turbo low-displacement V8 with direct injection, cylinder deactivation, variable timing and active engine mounts. As all manufacturers pursue better fuel efficiency but higher power outputs from their engines, these technologies will be seen in many cars very soon. Full details are available at Fourtitude.

The cars go head-to-head on a hilly track brought to you buy the boys at Autocar UK:

Motor Trend did this video of these three cars in action. Definitely worth a viewing:

How do you improve on an amazing supercar? Audi followed Lambo’s “superlegga” and Ferrari’s “Scuderia” ideals by making their V10 R8 lighter and increasing power, albiet slightly. The result is the Audi R8 GT. One-hundred pounds lighter and running a new 560hp version of it’s V10, this is a limited edition with only 333 planned to be made.

The weight savings were achieved by replacing the motorized rear spoiler for a fixed unit, more carbon-fiber panels, thinner glass, lightweight carpets and seats. With LED headlights and carbon ceramic brakes as standard, don’t expect this R8 to be cheap – it will probably push the price well into Lamborghini and Ferrari territory. Quite a feat for a German brand that doesn’t start with “P”.

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.

A video of the Audi R8 in the snowstorm that hit the Northeast: