Both Audi A3 and A4 are popular luxury cars that offer a great driving experience. The Audi A3 is a bit smaller than the Audi A4, but they both offer a lot of features and options. The Audi A4 has a bit more horsepower than the Audi A3, and it's also a bit more expensive. Both cars are great for long trips and offer a lot of comfort and convenience. The Audi A4 is a great car for families, while the Audi A3 is a great car for single people or couples. If you're looking for a luxurious and comfortable car, either the Audi A3 or A4 would be a great choice.