I test drove a 2006, but i bought a 2004. My 2004 has some minor mods which I think make a difference. When I initially drove the 06 I was straight out my M3, I loved the driving position and the ride, but it just felt a bit flat, however when I first drove my 2004 it already had a Kinetix Plenum and HF Cats and wow, i'm sure it made a recognisable difference.
As for the interior, I never really expected much, but I like Alezian leather and to be honest, it doesnt rattle and most of the time my eyes are on the road