I see this argument a lot: The A3 is identical to a VW Golf, just more expensive due to the four rings on the bonnet.
Coming from BMW's with this A3 being my first Audi, I wanted to investigate what actually makes the A3 different from its VW sibling. Its interesting the amount of technical data you can find if you really start digging into available information, shipping off some emails to engineers, etc.
I assume many here knows this already, but I figured I would just quickly sum up my initial findings. Im assuming this is mostly valid for other Audi's too, not just the A3.
To start with the obvious, the A3 shares a lot of common miscellaneous bits and pieces such belts, thermostats, starters, buttons, and what not, in the same way BMW's and Mini's now do. The 2.0 TDi engines are extremely similar, and the A3 obviously shares the MQB platform. MQB is however basically just a standardization of engine and transmission placement for cars with transversely mounted engines. Thats pretty much where the similarities end though.
The chassis is more sophisticated on the A3 than the Golf, where Audi uses aluminium on parts of the chassis instead of an all-steel frame. I was a bit concerned that I would be treated to the typical Audi front-heaviness understeering, but it seems like the 80Kg weight reduction on the new A3 is mainly in the front, which helps this somewhat. At any rate, panels, suspension points, structural reinforcements, tunnels, pretty much all the pieces that holds the car together are seemingly quite different in the A3 than in the Golf with the ones used in the Audi being a lot more sophisticated and generally of higher quality.
Does anyone else here have something to add? I'd be curious to know of any findings.