if this is the exhaust you are looking at
AAM Competition - Nissan GT-R, 370Z Turbo Performance Specialists
I have this setup and am happy with it. I've never had an aftermarket exhaust before so I don't have anything to compare it to. In the winter my hfc air sensors where throwing a cel so AAM had to add some piping to back the sensors out. I haven't had any issues with it since. When its cold and the pipes are cold they will definitely sound raspy, once they warm up though the rasp goes away. This system also hangs just as low as the FI system so lowering could be an issue if thats where you're heading. Zcarman and toohip both have the previous version of this exhaust where the muffler is tucked up underneath like the stock muffler. I also have hfcs and there is drone, there might not be any drone w/o them but I don't know. The drone is minimal in my opinion or I've just gotten used to it and it doesn't bother me anymore. I will say if I had to drive a numerous hours to go somewhere the drone might start to wear on ya after a while. Maybe at our meet this weekend someone will have a video camera and we can get another sound clip for you.