Engines: 4.2L V-8, 5.2L V-10. Transmissions: 6-speed manual, 6-speed single-clutch automatic. Models: R8, R8 5.2, R8 Spyder, R8 5.2 Spyder, R8 GT. The range-topping R8 GT gets a number of changes The 4.2 is a real beast. The problem w/ it is, so is its desire for gasoline (or maybe that isn't a problem for you). They're reliable but need TLC. With that said - the 3.6 will do just fine towing only 5500lbs. The V8 would likely be better.. but loaded and unloaded it will suck down more fuel than the 3.6 no question. Hello all, this will be my first of probably many posts. I hope to learn some good information here! I am looking at purchasing a 2012 Audi A8 L Quattro with the 4.2 V8 engine. I inquired the dealer to send me the vehicle history report and service records, they have yet to do so but the car appears to be in good condition and well kept. The Audi A6 C6 came out in 2004, so Audi has had six years to fix all reliability complaints for the 2010 Audi A6. CarComplaints only shows two complaints for the 2010 Audi A6. One is an electrical problem concerning an actuator failure on the driver door, while the other is a ticking timing chain tensioner. The mighty 4.2 is based on Audi's 4.0 V8, but features heavy revisions throughout to produce more power and better reliability. The interesting thing about the bigger V8 is that it has been utilized in two very different applications - as a quiet and comfortable luxury motor in the Q7, and as an all-out, high revving motorsport beast in the Audi's AQH, AVP, AYS and BCS were 4.2-litre, 40 valve V8 engines that powered the Audi D2 S8 from 1999 to 2003. Effectively replacing the 4.2-litre 32 valve AHC/AKH engines, key features of the 40 valve AQH/AVP/AYS/BCS engines included: A cast aluminium alloy block with 90-degree ‘V’ angle; Die-forged steel crankshaft with five main bearings; A6 / S6 (C6 Platform) Discussion - Timing Chain Reliability/General Reliability of Audi A6 2005 4.2 - Timing Chain Reliability/General Reliability of Audi A6 2005 4.2 I'm looking to purchase my first car and I haved up $8,000. I found an Audi a6 2005 w/4.2 lt Durability to heat and friction, weight, and space/area. These things make sense to me. Auto makers aren't stupid. I'm sure if they wanted to make a 1000hp Audi they could. Price, reliability and demand for such a product are reasons they don't. I don't believe its impossible. American muscle may be the smarter option financially. 8W81hw.