The dynatek definitely has had many issues. I had one when they first came out. Hard starting, trouble making changes with curvemaker software, would completely shut down at WOT for a second or two intermittently. it also will only add 30% more fuel than stock. That is enough for minor mods but not if you have duals and a cam. I had a good vendor who gave a full refund and I bought a MSD unit. I have had no problems with it. I have tried a 650cc injector with it but the injector was too big. The VDI may be a good choice taking into consideration having programming avaliable for the 109 injector, it wasn't avaliable when I was in the market.
About the duals. I have two bros and they are loud. I have also heard procircuit and dragonfire and they are loud also. I know a person who is working on an acoustic muffler that will supposidly flow well and not be as loud as most duals. He is going to also offer a removable silencer to get the unit back to stock noise levels, but says it will hurt performance. He has the summer/sport winter/hunt person in mind. If it works like he says it will be nice.