[Perfectlap]

There's no deficiency in the 911 and its one of the most visually appealing and recognizeable forms in auto world. (well no deficiency if you can deal with pendulus cornering-- I find that unerving and unacceptable) But I don't consider it a superior sports car to the Boxster. The standard Carrera has a bit more power but also weighs more and it's power is still somewhat underwhelming given its price tag. GT2/GT3/Turbo/C4S is enough extra power to make a different animal. But that's no more than common sense: you're paying a heck of allot extra for it!!
But for serious driving there's more than enough HP in both the Boxster and the standard Carrera. Take either out on the track and you'll be hard pressed to maximize the limits of either. So why do you need more if you've got enough to get you into trouble??

But Coupes are Coupes and Roadsters are Roadsters.

Two very different designs, purposes and experiences.

If I were in the market for Coupe and a Roadster I might be inclined to
make the Boxster my roadster choice and make the MZ4 Coupe my tin top.
I think the MZ4 Coupe has a much much nicer/racier interior, front end and
comes in at $25-$40K less than the rest of Porsche line up with decent power.