Space and practicality
Front space, rear space, seating flexibility, boot
That means it’s the RS4 that offers the more usable boot space, thanks to its extra length and larger aperture. The RS4 swallowed seven carry-on suitcases in our tests, whereas the C63 could manage only six.
The C63 does have some advantages, though. It has a smaller loading lip (just 2cm high), comes with a fold-out basket for your shopping and has one-touch switches at the boot opening that drop the rear seatbacks. The RS4 makes do with handles on the walls of the boot that do the same job but aren’t as convenient.
As for rear passenger space, the C63 offers fractionally more leg and head room, although there’s less space for your feet under its front seats.
Audi RS4 Avant
Official boot capacity 505-1510 litres Suitcase capacity 7
Both cars come equipped with 40/20/40 folding rear seats that might make your occasional trip to Ikea a far less stressful affair. However, the RS4 has a smaller step between the boot floor and folded seatbacks.
Mercedes-AMG C63 S Estate
Official boot capacity 490-1510 litres Suitcase capacity 6
C63 has handy one-touch switches at its boot opening that drop the rear seats, whereas the RS4 only has manual levers. Head room is reduced by the optional panoramic roof, but the C63 has more leg and head room than the RS4.
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