I've got the same exhaust setup as black metal and love it.
One thing we did do is rebuild the front part of the cat-back. The 3.5" DP goes into a 3.5" dump pipe, but the problem is the hooker cat-back flange is only something like 2.75" wide. We lopped off the piping just in front of the 2 into 1 and made a 3.5" flange swedged down to the dual 2.5's. If that makes sense? The exhaust now goes 3.5" into dual 2.5" with no restrictions. This really opened things up and changed the tone to a throaty sound.