This is an amazing car. I bought it used, but in great shape. It's got lots of power, especially after 6,000 rpm. =] The interior is great, the seats feel amazing, and the six-speed is wonderful. It has great fuel mileage, considering the type of car it is. This car is surprisingly big on the inside, which is nice. The Si Sedan is the best car out there for the money, and it's a Honda, so it'll run forever!
The Si seats, the six-speed, the gorgeous appearance (much nicer than the coupe, in my opinion) ^_^. And of course, the quality of a Honda.
There isn't much to be improved. The paint seems to chip easily, but that isn't a big complaint. Wonderful car.=)