I can weigh in on both cars. I owned a 2001 Audi A6 4.2 V8. Loved the car, I bought it used with 25,000 miles. Had plenty of power, luxury, fast, and a good looking car, but it cleaned out my bank account. The car was under warranty for a while, which helped, but the electrical problems that car had was unbelievable. I would never own one again. The transmission went, and new trans was about 6,000 parts and labor. Had to replace the whole instrument panel at 1100.00 a pop 5 times. Fun car to drive when it works right. My mother in law owns an Audi tt....and its a piece of shit too. I sold the car and got a 2006 Honda Civic Coupe. Almost 40 miles a gallon, 5 speed manual, and I bought that used with almost no miles for $12,000. I have almost 140,000 miles on this car. My daily driver, and the only thing I have done to this car since I bought it 4 years ago.......and this is truthfully speaking.......oil changes, and tires. Never a check engine light, never a failed sensor, I havent even had to change the brakes yet. I just had Lee(transman) change my trans fluid. Most reliable car I have ever owned, and I have owned 9-10 cars so far. If I had to do over again I would probably get the SI model. Those cars are fun to drive, 6 speed manual trans, pretty quick, and still ok on gas. Only thing is, the Civic SI calls for 93 octane. 200 hp in the SI, and limited slip diff. I am a big fella, and for a small car, they have plenty of room. I will buy another one for sure. So my 2 pennies.....stay away from Audi, and if you are looking for something fun and quick and want a civic....go test drive the SI.