Like most European cars, they break down frequently especially Audi's and BMW's.
The Ford Mustangs are versatile and cool vehicles, but unfortunately, the 2001 model years get a low score in reliability. However, I recommend Fords, I have a 2002 Explorer and it has never failed me yet and it has over 110,000 miles. Then engine in a Ford Explorer is very similar to a Mustang GT engine.
Mazda's are very reliable, fun, and efficient. I highly recommend this car, although it has a Rotary Engine instead of a cylinder based engine so the repair bills are slightly higher. The RX-8 just like all Mazda's do not break down easily.
The Honda Civic Si is very reliable like all Honda's. If you are looking for something sporty, reliable and economical then the Civic is for you. But the Si like all Honda's are boring to drive, have no style, and you will look ordinary and boring. Not to mention bad reputation teenagers a.k.a ****** bags drive Civics so police officers will see you as a threat, which leads to more traffic offenses. In addition, the insurance would be expensive due to the Honda Civic's reputation.
Mitsubishi's are unreliable, expensive, and have high insurance rates. The Mitsubishi Eclipse GT is similar to the Honda Civic Si. They are both attracted to deviants and police officers alike, and their reputation causes high insurance rates and unnecessary attention from police officers. Except for the fact that Mitsubishi's are very unreliable. Eclipse's engines tend to break down in the manner that would drain your wallet. The Eclipse is notorious for burning out engine gaskets, and cylinder heads. However, this does not happen to all Mitsubishi models, as long as the year of the car is 2006 or higher. The 2006 Eclipse or newer has more of a grown up yet sporty design which attracts females, and other good attention. Not to mention it is very reliable and it is much faster.
I highly recommend the 2003 Jetta's, as well as every Volkswagon that has ever existed. The Jetta is very reliable, fuel efficient, and safe. However, the fun factor is not that high, so it wouldn't be much of a car for you since you seem to want a sporty car. The Jetta, with some upgrades, can be a potentially fun car. I recommend the TDI (Turbo Diesel model) because it is very fuel efficient, clean, and it can be very fast. A Diesel engine has the potential to do almost everything from racing to hauling. The Diesel engine is very versatile and customizable. That is why Diesel is popular. Think of this, Izuzu build the most popular tow trucks, why? Because the engine only has a small four cylinder engine but has the equivalent power of any other tow truck with a bigger engine. The only difference is the Izuzu fuel economy is much better. So go with the advantage of having a turbocharger in your engine. Get the Jetta TDI.
The 2006 Chevrolet Cobalt SS isn't much of a car. Although the engine is fast, fuel efficient, and reliable, the quality of the interior and exterior body is pretty bad. Many have reported problems with the sunroof, dash boards, and electric components. Overall it is a good car, but it's not recommended for those who look for quality in the interior and exterior body.