I believe the difference between the I & II were minor. I think they used the same drivers but had some slight cosmetic, weight and tuning differences. The series III uses a totally new driver and tweeter. I had the I and bought the III kit and put that in mine before selling it.
Edit: It's coming back to me now. The series I used the spray on liner finish. The II used the tolex finish.
Last edited by jjk2007 : 10-28-2013 at 08:39 AM.