I'm also running the 6.5" BDS coilover. What block size is your rear end sitting on? Could you post some pics and information about the Sulastics? What was required for the installation? I've read that the body is in the way on the HD, which requires a good bit of extra work. True? This is probably my next install, but I've been hesitant.
I like the look with no pipe. I've dumped my last two just behind the axle. I also have a Flowmaster - mine's the 50. I don't see many running this dumped exhaust setup.