The ATI super damper is probably the best as far as dampening goes, but it is only available up to a 10% underdrive. The March fluid filled damper isn't very far behind in dampening ability and when you consider that the fluid is not rotational weight, is also pretty light. The SLP/Powerbond has tall walls to help prevent thrown belts. The ASP is probably the lightest out of the bunch, but is not known for it dampening ability. It's your decision, but I tend to lean towards the March damper as the best all around underdrive damper IMO.