RR,
Although I have built my share of 2 and 4 stroke pipes, I have not been able to try, or see the Hydro process. As I understand it, it is in a nutshell 2 pieces welded together in a predetermined flat shape than water ballooned into shape. That being said, RR, you can contact Tomcat Loftis over at the Worldwide Triples forum, for I believe he knows alot about it.
Jimbo,
First just let me say, I love the street perf sound of seventies 4 into 1 pipe with a megaphone muffler. That being said, after you experience a M3 engine breathing out through cr750 4-4's wide open at Daytona or standing next to it in the pits, it is the true sound of power from these engines. Ultimately, one pipe per carb is the free-est breathing way to go which is what you want when you want to stay in the upper powerband. In 05' at Daytona there were two works MV Agusta's there and I stood about 20 feet behind one when it was being warmed up and it sounded somewhere between the cr and the RC166 6 cyl.
So basically, I would say it's all good it just depends on what you want. I just don't like quiet!
HB