Put a short ram intake on it, that would give you an acceleration growl up front from the engine bay. Put a header on it, so maybe you'll get a little bit of torque to go with the sound that says you have a lot of power, also some tone.
Remove the resonator, it's going to get really raspy. Increase the diameter of the exhaust tip, same deal.
This sounds pretty dumb, what exactly is the point? Do you have any power to back up all of the noise your car is making, or you just want to turn heads, so they notice you're not really going as fast as you sound like you are?
My girlfriend's car came with a full catback system by Magnaflow with a large diameter exhaust tip. It was really loud and pretty deep, never raspy, no matter what rpm I took it to. If it would have fit your car, I would have given it to you instead of the garbage can, but that's something you could look into.