This is my 2nd Z. My first was an 03 Enthusiast with the 5A. I couldn't stand the car. I had it only 6 months and sold it. I bought my 06 last August. It's the base model with the 6 speed manual. This is the most fun car I've ever owned. It's a complete 180 from the 03. The exhaust note is amazing, gas mileage is awesome for a 300 hp car, and the reliability can't be beat. This is my weekend car, while my 07 Audi A4 is the daily driver. The Z gets a little bone-jarring after a while, but I always have a blast driving.
Acceleration, build quality, brakes, gas mileage, fit and finish, and suspension.
The seats are uncomfortable and I have trouble finding a sitting position (I'm 6'0) without being at a 90 degree angle. It's awkward. The standard radio is awful. Finally, make traction control standard. If it rains, the car slips and slides all over the place.