These are very nice sounding subs, but they are heavy and very fragile. I have had a sound system in my car with these subs for about a year and blown them three times. Apparently the heat in Southern Louisiana is to much for the subs to handle.
I have experience with these drivers, and the best thing you can do, is buy an extended warranty on them from the place you buy them from. Places like Best Buy offer the Performance Service Plans for 4 years for $40. Blow the speakers, get new ones...its as simple as that