Useful Idiot....Symphony X is a great band if you like that pussy-lead singer voice..you know, like Dream Theater. I am not saying it is bad, but it is higher pitched..(and I like Dream Theater and SYMPHONY X a lot)
Extremely heavy guitar and drums ...they have fast guitar and drums, but not real heavy..
Not all super-fast songs ....yeah this fits...but they can play fast
Low scream/growl similar to Meshuggah or later Opeth ...lol, not EVEN close
High technical proficiency ....yes, in fact, the lead guitar is one of the best out there....no joke.
As far as testing out songs, just put in their name into a search, and anything that pops up is going to give you a taste of what they can do..but unless you like your lead male singers to sound like they have had their balls cut off, you are not going to like them, even if you are blown away by the guitar...