Im a Boxster owner - (not a 911). Bought the 2005 version as it has almost as much ooomph as the old Boxster-S at 240HP. PSM [Porsche Stability Management] is standard in the new Boxster [was a $1200 option in 2004]. PSM is nothing but traction control and it saves people like me who do not have the talent to drive fast.
The Boxster is [for me] the most attainable mid-engined car in the world - the next step up is a Ferrari or a Lambo that costs four times as much.
The Boxster shares everything from the front bumper to the drivers seat with the 911 [997] and that includes the newly rounded headlights; and almost 60% of the car is Carrera derived [and this is a nice thing]. Steering, is razor sharp - and the mid-engined layout is confidence building [it takes a much better driver than me to go fast in a Carrera (which is what the Carrera-4 is for - the talentless ones with ooodles of money)].
Anyway, the Boxster manages 0 to 60 mph in 5.9 seconds, and upwards of 3000rpm, it pulls like a champ in any gear. The engine screams above 5K rpm - which keeps you reaching for the higher revs on every gear-change.
Which brings us to the brakes.... the best bar none. The Boxster had numbers worse than only the $440, 000 Carrera GT in Road&Tracks tests - with 60mph to zero in like 109 feet.
Maintenance: The first service is at 20, 000 miles or 2 years, and the dealer says that it will cost some $200. That makes the car cheaper to maintain than most Hondas or Toyotas.....
Overall, it is the best car that I have owned and Ive enjoyed every minute of ownership......