OK, sophisticated may be a bad word for this thread. Maybe the word should be refined. Because in every description of sophisticated that has been given, refined would fit much better.
And to say that the MS3 it is targeted towards young people is unfair. Maybe in FL you see a younger crowd, but up here, there is no "crowd" at all. Young, old, and everything in between drives speed 3s and regular 3s. Same thing with the 6s around here, there is no target demographic. I could say the same thing that you said about other meets. I went to a Nissan meet last year where there wasn't anyone over 30 in attendance, that doesn't mean that Nissan makes its car for "boy racers". Ok, to me, boy racer is that ugly TRD Celica that came out a while back. The wing on the back of EVOs and STIs is "boy racer". Especially the STIs, that thing isn't even functional. Cobalt SSs are "boy racer". SRT-4s are "boy racer". Sitting next to any of those cars, the MS3 looks like a grocery getter. I still don't see the Speed 3 being "boy racer", but, to each his own. You see your car as "boy racer", I see mine as "sleeper".
I've not been privileged to see the inside of a MS6, I have seen a regular 6. Eh, it being sooo much nicer than the interior of the 3 might be an overstatement. Its nicer, but not like honda to lexus nicer. Besides, I think the interior of my GT is pretty nice. Again, neither of these cars are luxury cars so how much refinement are you really looking for in your interior? Its not an Audi, or Bimmer, or Benz. Its a Mazda.
Like I said though, you like what you like. I drive my MS3 not because I'm some kid who just got his license and wants to race everyone everywhere, but because I got a whole lot of car for my money and liked the styling. Period. If the OP feels that he gets more bang for his buck with the 3, so be it. If the choice were so obvious, I don't think that the OP would have even started the thread. Each vehicle has its up-side, and down-side.