The BRZ and the FRS are the same car, I think. It's a joint project between Scion and Subaru, the BRZ just has more "standard" features, plus a higher sticker.
It's my understanding that they are underpowered cars. Here's a drag race involving both Porsche and the BRZ (FRS, FT86, whatever you want to call it)
The World's Greatest Drag Race 2! - Motor Trend
I understand the temptation; the rear seats fold down, so there's some cargo capacity. But I thought that overall it looked a little cheap: the dash was a mess, the all black interior annoyed me, and the paint finish was begging for clear coat.
Have you considered a used Lexus F Sport? Decent size, with rear seats, good trunk, and an engine roar to rival a big engine American car. It's basically the same size as a Lexus IS350, but with a bigger engine and sporty interior. They are hard to find, but I drove one and it was very close to the Boxster. I didn't care for the black interior, on the one I test drove, so I passed on it.