This has been a great car. I drive a lot of highway miles. Have about 10K on it already. I can get up to 33-34 mpg on the highway. I'm a big guy, 6'1" 245lbs and I fit just fine in it. That was my worry before I test drove it, but I checked it out and there's plenty of room for me. The only thing that I'd like to change is the seat material. I got the sport cloth and it seems kinda cheap, so I will get leather put in eventually with custom seats. My brother, who has a Lexus IS300, loves my car. He says it really flies, and handles really well. The SS suspension is really tight and stiff. The engine growls when you punch the gas, and the auto tranny is really smooth.
Fast, smooth engine. Good horsepower for a 4cyl.
The turning radius in the SS models is terrible. Hard to make a uturn sometimes. Other than that, there's nothing to improve upon IMO.