Resonator

What does the resonator do on the b-pipe? Should I get a b-pipe with or without the resonator?

the resonator's basically a sound dampener. just makes it run quieter.
as far as what you should do, it depends on what you want for sound.

does the resonator restrict on flow though? Quieter has always been cooler to me, except when at WOT. That's where i want to growl.