Only an anecdote, but my feelings about classical are somewhat mixed. IQ tested as a child, but results varied quite a bit from test to test (mostly because I'm literally autistic and didn't cooperate half the time). The ones where I did put me at 148 (Raven's) and 164 (WISC VCI, extended norms). I took my first graduate math course when I was 16 and currently have a 4.0 GPA in college. I'm no genius, but I think I at least qualify as reasonably intelligent.
Bach is enjoyable, especially the fugues, but only in moderation. If I listen to too much classical it starts to wear. Metal is probably my favorite genre overall.
Also, see the (very unscientific) results from
http://musicthatmakesyoudumb.virgil.gr/ 
