First thing to address is the infamous oil pump seal problem with the RS6. The seal itself is a cheap 50p component, but getting to it is difficult. It can be done with the engine in place for around £1,500, though some mechanics prefer to remove the engine and that will cost £4,000 on its own in labour charges.
Fast with 580hp; imagine it with 700 plus...
To check for leaks from this seal - it dries out because under-bonnet temperatures are so high - look for leaks underneath the car. Also, if you look to the right of centre at the back of the engine you should be able to spot any seeping.
The oil temperature sensor can fail and is pricey to fix as it's positioned within the depths of the engine. Reckon on £500 to cure this due to the amount of labour involved in reaching the sensor to replace it.
Coolant can leak from two pipes in the driver's wheelarch that are hidden behind the arch liner and rot through. This is another costly job to put right due to restricted access, which can mean removing the engine. However, several Audi specialists can now replace only the corroded sections without taking the engine out, bringing the repair bill down to about £700.
A wise precaution is to change the transmission fluid at 20,000-mile intervals as it takes a pounding from the engine's torque. It's supposed to be a sealed for life unit, but there have been incidents of the six-speed ZF gearbox overheating and failing.
Best get it serviced at a specialist to save money
Engine remapping is a common upgrade for the RS6 and it's easy to obtain more than 700hp and 700lb ft of torque in place of the original outputs. That sounds a lot for a family saloon or wagon, but the engine can take it very well and reliably. Spend another £500 in addition to any engine tweaks on a gearbox remap and you'll enjoy faster changes. Yet another popular modification is to swap the original exhaust for a Milltek system to get a better noise and more power.
When it comes to servicing an RS6, a specialist is the way to go to save money as they will charge around £600 for a minor overhaul and £750 for a major service including spark plugs. Go to an Audi dealer and you'll pay £700 or more for a minor check-up and more than £1,000 for the big one.
PHer's view:
"It probably goes without saying that they are an incredible vehicle and a masterpiece of engineering."
Andi Parker