It’s always fun to watch two direct rivals go head to head and see who’s better at accelerating in a straight line. It’s even better when both cars are heavily modified.

We’re happy to see that this wasn’t one of those unfair battles we get to see every now and then. There’s no major difference in output between the M5 and the RS6, which means that it’s all about weight, torque and transmission.

Of course, keep in mind that this is a rolling start and the Audi‘s all-wheel drive system isn’t as helpful as it would have been if both cars went flying off the line.

If this was a standing start, the RS6 would have hit 100 km/h (62 mph) in 3.9 seconds, whereas the M5 would have needed 4.3 seconds – when stock. Also when stock, both would have had 560 HP and similar torque figures (680Nm/501 lb-ft for the M5 and 700Nm/516 lb-ft for the RS6).

Then there’s the weight difference we need to consider. The M5 is normally about 75kg (165 lbs) lighter than the RS6, which is roughly the weight of an average-sized male passenger.

Now for the specs in question. Thanks to a Burger Motorsports ECU tune, AFE air intake & carbon scoops, AMS downpipes and a few other mods, the BMW M5 is good for 700 HP. Yeah, that’s pretty good, but the RS6 is right there with 690 HP of its own.

There you have it. Who’s your money on?

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