gt2 four seater?

hey, is it possible to make the 996 gt2 a four seater? There is some space at the back, i wonder if you could just put some seats back there?
If it is possible does it require alot of custom work?

http://www.auto-salon-singen.de/porsche/porsche_996gt2_si_sw_2001_2501_03_10.jpg
http://www.stig.uklinux.net/images/tech.jpg