Watch: The RS4 Avant and the RS6 Avant Go Toe-to-Toe Share Comments Although the RS6 Avant has a couple more cylinders than the RS4 Avant, it also carries a few more cubic-feet of size. So, just how much lap time does that it all amount to? AutoBild sought to find out and took these fine Audis to the Sachsenring to let them loose on a good bit of road. Starting with the acceleration test, it’s actually very close, for the first 100 km/h at least. On video, the RS6 gets to 100 km/h in just 3.4 seconds while the RS4 gets their in a more than respectable 3.6 seconds. After that, though, the bigger car’s bigger engine starts to stretch its legs pull out a lead. Getting to 200 km/h (120 mph) in just 11.9 seconds, while it takes the RS4 13.7 seconds to do the same. Fortunately for the RS4, it seems there aren’t that many 200 km/h sections—or the weight advantage plays out in the corners—because the RS4, although slower than the RS6, finishes the lap less than a second back when they’re wearing the same tires.