I think Bruce's point is that it matters not how much HP a car has as long as its enough for its weight. Take a trip to your local track and you'll se a ton of 150 HP Miatas.
500 HP is just as practical for the track as it is for streets.
You are aware that the VAST majority of Porsche owners never go near a track with their 250-400 HP cars? For street use that's more than enough power.
So a free breathing Boxster/911 is just as impractical as z06.
even if it feels funny cruising on the highway in 2nd gear
Believe me if these cars didn't run a $3 a gallon 93 octane I'd drive one everyday to the 7-11 or Starbucks.