Motorcycle Repair: Twin Cam Cams 4 degree advance, screamin eagle cams, performance changes

Question
I have heard good things about 4 degree advance gear drives, yet they don't seem all that popular.Seems to be the way to bridge the gap between bolt in cams, and the bigger HP cams, and keep some low end torque. I don't want to give up the torque for rarely used, high end Horsepower. Any insight would be greatly appreciated.

Answer
Sorry John I don't have any first-hand info.  Gear drive cams of course will have "gear whine" as opposed to stock chain noise.  But Harley offers a number of different Screamin' Eagle cams for different results like low, mid, or high end performance changes.  We've had good luck with them.