I am a reasonably keen driver and have always bought various older high performance BMWs, Audi's and even a Porsche Boxster over the last 20 years, and have whittled down my choice of next car to either a 2005 Audi A4 B7 3.2 V6 or a 2005 Audi A6 C6 4.2 V8. I have always found the Torsen quattro vehicles preferable and better overall for road driving - something BMW finally acknowledged by fitting xDrive throughout its range (not all available in RHD). Common sense and previous experience means that I'm aware that cars at this age can and do incur occasional expensive problems, but since I will be keeping it for at least three years I accept this. I will only be driving about 7000 miles a year.

My concern is mainly the reliability of these two engines and relative repair costs. I have had several V8s and not had any issues with them and so am inclined to go for the A6 V8, but also feel that the A4 would be a slightly more sporty drive, albeit with the V6 engine. I realise that both have chain cam engines but have read that both have a slightly common trait of suffering from complete engine replacement due to the tensioners snapping, and not always due to poor maintenance either. Finally, with regard to the ZF auto transmissions for both, I presume that you also recommend oil changes for these in the same way that you do for BMW "sealed for life" (ZF/GM) units?