Hubby has a 2001 911 and I have a 987. They are completely different cars.
The 911 has more horsepower, but the rear end will swing out when autocrossing. I've seen it.
It does feel heavier. More torque feel, slightly less responsive steering.
The 987 is more agile and responsive, but has slightly less horsepower. I'm (ONLY) a second slower in the straight aways.
It feels light, which disguises it's power. Smoother, less torquey.
We have been folding our kids into 911 rear seats for years, but neither car is practical.
If you like a 911, then get one. But I think after a couple of months, you won't really feel a lot of difference, in everyday driving.
If you're autocrossing, you'll miss the Boxster. I love the slaloms, they're my favorite thing in the world. Hubby feels like he's fighting the car around every cone, because the inertia shifts from side to side. The boxster doesn't have this inertia.