2007 BMW 3 Series 335i 4dr Sedan (3.0L 6cyl Turbo 6M)
I've had many cars in the past including AMG cars and this 3 series is the best combination of performance and comfort by far. It handles like a slot car, pulls like an M3 and is just as comfortable as any car in its class. The interior is top notch and it's plenty roomy for this size car.
Engine (300hp/29mpg). Suspension (sport package) and quality materials in interior.
I'm sure BMW can tweak another 40 to 50 horses out of this engine.